Choosing wind resistant trees
Now that Hurricane Matthew is gone and some of our trees came down there is often a “knee jerk” reaction to take all the trees down from around the house. Perhaps we need to take some time and rethink this position because trees provide so much to us and the environment. If trees need to be replaced then let’s consider planting some tree with high to moderate wind resistance. But, before I give you a list of trees to replant I want to mention we can make a good selection but do the wrong things to trees and alter their ability to withstand high winds. Over-pruning trees or using improper pruning techniques will directly alter the trees ability to withstand storms. Do not cut the top off the tree, no lion’s tail cut which generally removes the interior foliage. No over-pruning to “raise the canopy.” Be sure to call a certified arborist to prune trees. Planting trees too deeply will show limb dieback on the tree very early. Over-mulching - NO mulch volcanoes, mulch should only be 2-3 inches deep and never be close to the trunk of any tree of large shrub. Over-watering – we should not water trees and shrubs the same way we water grass. After a few years the trees and shrubs do not need irrigation unless we do through a drought period. Growing grass up to the trunk of the tree - grass and trees are terrible partners. The things we do to grass we should never do to trees. Leave as large an area as possible with no grass. Planting large shrubs around the base of the tree is a poor practice. Adding soil to the roots of the tree – even a few inches can cause a loss of air around the roots. This following information was taken from research done by the University of Florida in 2005 titled, “Selecting Tropical and Subtropical tree species for wind resistance.” 1. One of the most important findings is the rooting space: the more rooting space that a tree has, the healthier it is, meaning better anchorage and resistance to wind. 2. Trees growing in groups or clusters were also more wind resistant compared to individual trees. This might be an especially good strategy for tree establishment in parks or larger yards. Especially significant for those green belted areas. 3. Proper should be considered an important practice for tree health and wind resistance This list is not all of the trees but it will give you a good place to start: Highest wind resistance for North Florida: Carya floridana, Florida scrub hickory; Conocarpus erectus, buttonwood; Ilex cassine, dahoon holly; Lagerstroemia indica, crape myrtle; Magnolia grandiflora, southern magnolia; Podocarpus spp, podocarpus; Quercus virginiana, live oak; Quercus geminata, sand live oak; Taxodium ascendens, pondcypress; Taxodium distichum, baldcypress; Butia capitata, pindo or jelly; Livistona chinensis, Chinese fan; Phoenix canariensis, Canary Island date; Phoenix dactylifera, date; and Sabal palmetto, cabbage, sabal.
Q: We were thinking about planting a tree to be used as a permanent Christmas tree for our yard. We noticed you have two in the demonstration garden, the Southern Redcedar and the Arizona cypress. Which of those two do you think would be a better choice?
A: Good question. Both are evergreen and have the Christmas tree (pyramid) shape and they both would make a nice addition to any landscape if you have enough room. Southern Redcedar, Juniperus silicicola, can grow to 40 feet tall with a 25 feet spread. It tolerates most any kind of soil and light conditions – full sun to light shade. Southern Redcedar is very drought and salt tolerant. It has very few insect issues but there are a few fungal diseases which can cause twig die back of leaf galls. Most of the diseases can easily be pruned out and controlled without chemical applications. Arizona cypress, Cupressus arizonica var. arizonica grows to the same height and spread as the Southern Redcedar, likes similar planting conditions although we are not sure about its tolerance for salt spray. Arizona cypress has a slight bluish cast to the leaves especially on new growth. It has no real insect enemies but has been known to develop blight in cool, humid conditions as well as stem canker. One big difference, Southern Redcedar is native and has been known to attract birds while Arizona cypress does not. I don’t think you could make a mistake by planting either one but I like the idea of having a native tree in my yard which is able to supply food for birds. But don’t let me influence your final decision!
Southern Redcedar: http://edis.ifas.ufl.edu/st326
Arizona Cypress: http://edis.ifas.ufl.edu/st222
Q: We are trying to select trees to grow along the street areas of our homeowner association and were told not use Chinese elms as they can easily get uprooted during a storm. What do you think? Is that a true statement?
A: We learned quite a few lessons after the four hurricanes came across Florida in 2004. Chinese elms, along with Bradford pears, Leyland cypress, water and laurel oaks and the Washington fan palm are the least wind resistant in our area. The most resistant to the wind were dogwood, crape myrtle, holly (American, yaupon, dahoon), magnolia, oak (sand, live, turkey), bald cypress, podocarpus, sparkleberry, and some of the palms (Pindo, Canary Island Date, date, cabbage). Our native winged elm fell into the medium resistance group along with Japanese maple, river birch, red bud, fringe tree, and several other oaks. Attached is the full list of high resistance to low resistance according to the area of Florida. However, it is important to keep all trees in the best health. Even the strongest resistant trees can fall if the roots of the tree have been compromised by construction or other environmental factors. Remember, do not allow mulch to pile up against the trunk of any tree or shrub as this can lead to water damage on the trunk and potentially introduce disease. Over pruning or improper pruning, even if it is called “hurricane cutting”, may cause more damage and make the tree susceptible to failure. Trees should not be shaped like gum drops, hat racks or lollipops. Be sure to call a certified arborist when it is necessary for your trees to be pruned.
Q: In one of your teaching sessions you mentioned not piling mulch up around the trunk of trees. Everyone does it, so what kind of problems does it cause?
A: Good question and I actually have a couple of photos which show the water damage on a crape myrtle from too much mulch or mulch “volcanoes”. I wish mulch volcanoes were not a common practice in landscapes and on commercial property. I believe it will take some time before we can change this inappropriate practice, but we keep trying. The photo shows the moisture ring caused by the mulch piled up at the trunk. In this particular case, the mulch was only there a few months so we were able to move the mulch off and allow the trunk to dry. Therefore, we don’t believe there was any permanent damage. However, think about the potential of this moisture remaining for long periods of time on a thin bark tree trunk. The piles of mulch can potentially allow for fungal disease to enter into the tree. Consider how damaging this could be for the whole tree if the bottom of the tree trunk is compromised. Trees in urban settings have enough stresses without putting on additional ones such as too much mulch and moisture. This is so easy to fix. Remove the mulch from around the base of the tree and move it out (2-3 inches deep only) under the canopy of the tree. While you are removing the mulch, you might also check to see if the tree has too much soil on the roots too. The combination of the two (too much mulch and soil) can prove deadly. The photo I included shows circling/girdling roots really close to the trunk – not a good thing either. All these issues (too much soil and mulch, circling/girdling roots) can be corrected at the same time. Your tree will be so appreciative and happy.
Q: We went out of town on Thursday and came back on Sunday. Upon returning we noticed our Red Maple tree was completely dead. What could have happened?
A: The quick kill on this tree, and any tree for that matter, was probably caused by lightening. Nothing else will kill a tree so quickly. Diseases or insects will work on the tree over weeks and months therefore it will take much longer than a few days to turn totally brown. We did experience storms and therefore possibly lightening during the time you were away from home. Nothing can be done to rectify this now. The tree will need to be removed if there is any potential of it falling on your house, your car or other people. You can cut the top out of the tree and let it remain in your yard to provide a home for other wildlife such as the Pileated woodpecker. Dead trees left in the landscape for wildlife are called snags. As long as the tree is not at risk for falling on people or things it should remain, if possible. It is important to also note lightening does not have to directly strike the tree to cause extensive damage. It is possible for the strike to occur on the ground, travel around the root area then go through the root to the rest of the tree causing death.
Q: I have a tree in my yard that was here before I built my house. How can I tell how old it is?
A: The only way to know for certain how old a tree is to either cut it down or bore into the bark. The first method will obviously kill the tree and I am sure you do not wish use that procedure. The second method requires a special tool called an increment borer. An increment borer puts a permanent hole in the tree which can potentially introduce disease. A perfect cross section of the tree is removed by the borer. The rings are then counted which would enable us to determine an approximate age. If you believe you have a large, champion tree consider contacting the Nassau County Forester, David Holly. He would definitely be interested in checking your tree out. If you indeed have an old or very large tree, David will assist you through the procedure of how to add your tree to the Florida registry. I know you did not ask this question but the study of tree rings to calculate age is called dendrochronology. Sounds like the perfect trivia question to open up a normal family dinner conversation doesn’t it?
Q: I heard you speak in one of your plant clinics about the problems of trees and shrubs being planted too deeply. You talked about removing the soil from around the root area. What I don’t understand is how you know when a tree is planted too deeply.
A: Sir Arthur Conan Doyle’s famous character, Sherlock Holmes, would reveal the secret to his deductions and often he would be told how elementary and obvious his answer once the connection was shown. You will shortly see how easy it will be to determine when a tree or shrub is planted too deeply in the ground. Trees should have a natural flare at the bottom of the trunk where the root structures are formed. A tree which is planted too deeply will look like a fence post rather than a tapering tree. Ah, that is elementary! Well, yes it is. Research provided through the University of Florida by Dr. Ed Gilman has shown twig dieback, reduced branch and foliage growth occur on trees planted too deeply in the ground. The upper most root structures should be just at or slightly below soil level as too much soil on top of roots restricts oxygen to the roots. Restriction of oxygen to the root structures reduces the root’s ability to absorb necessary water and nutrients. The best cure for trees planted too deeply is to remove the excess soil from the root area. Leave about 12-18 inches around the base of the tree with nothing but a few inches of soil. Then mulch lightly outside the area with 2-3 inches of mulch, preferably using organic mulch as your first choice. For those of you whose soil is slightly alkaline your best choice of mulch is a pine product such as pine straw or pine bark. Check out Dr. Gilman’s solutions for too deep planting: http://hort.ufl.edu/woody/rootgrowtheffectsdeepdet.shtml
Q: I have a beautiful tree in my yard that has greenish, white tassel-like seed structures hanging in clusters from the tree. Can you tell me what it is?
A: Thanks for the photos. This tree is an ash. We have several species growing in our area. The White Ash, Fraxinus Americana, Carolina Ash, F. caroliniana, and the Florida or Swamp Ash, F. pauciflora. The White Ash is a large tree and the only one that inhabits well-drained sites. The other two species are small to medium sized trees that tolerate wet areas. I suspect your tree is the White Ash.
Q: I live on Beech Street and I would like a Beech tree. Will you recommend one for me?
A: The American Beech, Fagus grandifolia, needs enough room to spread out 40-50 feet. This tree should be planted on large estates and I do not believe your landscape would be able to sufficiently support this grand tree. In addition, the cold hardiness for this tree is zone 8 and you are in zone 9a. Although the hardiness zone is on the edge, it would be an additional stress for the tree. I would suggest you consider the American Hornbeam, Carpinus caroliniana, which only reaches heights of 20-30 feet with the same spread. Although it is not a true beech tree, it has a common name of Blue Beech because its bark has a bluish hue and the leaves are similar in shape to the American Beech tree. American Hornbeam is slow growing, so it would take some time to grow tall. It also is better suited for our hardiness zone. The American Hornbeam is an under-utilized, native tree perfect for the smaller residential landscapes. It prefers acid soils and the small fruit and buds attract birds and squirrels. The American Hornbeam can grow well in full sun or filtered light.
Q: Parts of my bottlebrush tree are dying and it appears to be growing leaves and flowers only on one side of the tree. What would cause this?
A: I appreciate you bringing me clippings of the tree. It was especially important to bring in limbs with living leaves still attached. It is often difficult to determine the cause of a problem if the only material I see is totally dead. I was unable to locate any disease or insect damage so the next thing to do is look at the root area. In several recent instances I have found the same damage you described and discovered girdling roots at the base of the tree. A girdling root is similar to having a tourniquet wrapped around your arm. What will eventually happen to your hand if the tourniquet is left in place for a long period of time? Your hand would have the blood supply cut off and the limb would be lost. The same thing can happen to a tree branch if a girdling root is allowed to grow around another tree root. We recently panted fourteen new trees at the James S. Pages Governmental Complex and every one of these new trees had some degree of girdling and circling roots – from mild to severe. It is important to examine the root ball of any tree or shrub you plant. Remove those girdling or circling roots before you plant. Remove the top layer of soil and root mass so you can examine the root structure carefully. In your situation, the plant has been in the ground for several years but it is still important to remove any roots growing into another root. Cut the girdling root just above where it starts to grow over the other root. You may need to use loppers to make a clean cut. Do not add any amendments to the soil – no black cow or fertilizer. Just be sure the plant is well irrigated for a few weeks to help get it through the shock of losing a major source of water. Keep lawn grass as far away from the roots as possible. Be sure the mulch is not too deep – only about 2-3 inches. Never allow mulch to be piled up around the trunk tissue, which can provide the perfect environment for disease. Allow 18 – 24 inches area around the trunk of the tree or shrub which should contain nothing but soil and air. The attached photo demonstrates what can happen if the girdling root is allowed to get too large. Girdling and circling roots are probably one of the more important causes for failure in newly planted trees. For more complete information regarding removal of girdling roots please check out the UF/IFAS Environmental Horticulture website: http://hort.ufl.edu/woody/removecircling.shtml
Q: What is wrong with my Bradford pear trees? There are spots all over the leaves.
A: After looking at the leaf under the scope it was evident that your tree has Entomosporium leaf spot, which is a common problem in all members of the rose family including Bradford pear. Spots may enlarge and merge to form larger blackened areas.Tiny black specks, which form spores, can often be observed in the center of each leaf spot. Severe infections often result in early and heavy leaf drop. Heavy leaf drop severely reduces its landscape value and can cause plant death.
While fungicides may be helpful, the disease is not curable; and cultural management practices will probably be more effective. Space plants to improve the air movement around the plants and promote rapid drying of leaf surfaces. If plants are overgrown, consider removing every other shrub to allow for better air circulation. Avoid overhead irrigation as this spreads the spores from leaf to leaf. Trees and shrubs should be irrigated at the root area only. Remove fallen diseased leaves; do not use them as compost or bedding mulch. Establish trees and shrubs do not require the same irrigation and fertilization as lawns. Excessive nitrogen and water promote weak stem growth which will intensify the problem. Severely defoliated plants may need to be pruned to reduce the source of spores and improve air circulation. As a last result, you may need to remove severely diseased plants and replace them with another plant species that is not susceptible to leaf spot.
Q: I just moved here and I have this tree in my yard which has clusters of white seed pods. I am also seeing loads of seedlings all underneath the canopy. What is it and should I be concerned?
A: This tree is a Chinese tallow tree and it is classified as a Class I invasive plant by the Florida Exotic Plant Pest as well as the Florida Noxious Weed list. It has been a time consuming pest for the City of Fernandina Parks and Recreation as they have worked tirelessly to manage it in Egan’s Creek. In China, Chinese tallow, Triadica sebifera, is cultivated for seed oil. During the 1700’s, Chinese tallow was introduced to the United States primarily for use as an ornamental tree. It was also introduced for making soap from the seed oil. Not only has Chinese tallow become naturalized in the southern coastal plain from South Carolina south to Texas, it has become naturalized in over half of the counties in Florida. Characteristics which make Chinese tallow a popular ornamental are its fast growth rate, attractive fall color, and its ability to resist damage from pests. It is a small to medium-sized tree that grows to about 20 feet tall, but some specimens can reach 40-50 feet. The fruit is a three-lobed capsule (0.5 inches) and seeds are covered with vegetable tallow, a white waxy coating. Fruit ripens from August to November. We would recommend you remove it but now might be the best time as it is loaded with seeds. If you try to remove it now, the seeds are likely to spread. The seeds have a very high germination rate. This publication will provide more information about proper removal. http://plants.ifas.ufl.edu/node/399
Q: I have a friend who has a sloping piece of property with bald cypress at the low end. The intention is to build a house and level the property. How close to the bald cypress can we get with fill dirt and not cause a problem for the tree? Can I build a well around the tree and fill in the whole area?
A: I am so glad you asked me this question before you filled in the area with dirt. The ideal scenario would be to imagine a circle 2-3 times the drip line and add no fill dirt within that circle. The drip line is the point where the tips of the branches end. But since that area is probably the whole yard we should consider other choices. Try to keep as wide a berth around the tree as possible; adding no fill dirt to that area. Consider a circle from the trunk out to the drip line as a minimum area. Roots require soil full of air (about 50%) and adding fill dirt to the landscape greatly reduces the amount of air available to the roots. The roots in turn suffocate resulting in the tree eventually dying. The process is slow; it may take 3-7 years for the tree to totally succumb to the loss of roots. In the mean time, the tree may develop a fungal disease on the branches or borers will suddenly appear. These pests are really only opportunists and they come in once they sense the tree in dying. Some people may fault the fungus or the insects but the root of the problem (excuse the pun) is the fill dirt. This problem is true of almost all trees, not just bald cypress. Well structures have been constructed around trees particularly those of special interest to property owners. Building the well is expensive and labor intensive, however research did not indicate it was especially beneficial. Ultimately you must decide if the trees are important enough to keep and then grade the property accordingly. Just one more hint about building and trees, keep all heavy vehicles away from the tree roots because soil compaction from constant foot and vehicle traffic can kill the tree too. By the way, Bald Cypress is not only a great tree near water sources, but it makes a terrific landscape plant too. It is drought tolerant once it is established and can live in a variety of soil environments.
Q: I am thinking of planting Arizona Cypress as a windbreak. What kind of environment does this tree prefer?
A: The Arizona Cypress, Cupressus arizonica, is a native of North America, grows quickly to heights of 30-40 feet with a limb spread of 15-25 feet so give it plenty of room. It has brown bark that naturally peels and grays with age. It is very drought tolerant so be sure to plant it high and dry. Arizona Cypress requires full sun but can tolerate a variety of soil types with the exception of clay. The tree roots do not develop a strong hold in clay soil and the tree has been known to topple when planted in clay accompanied by strong wind gusts.Some locations along the east coast are too humid for this drought tolerant plant and Arizona Cypress has been known to develop juniper blight as a result.
Q: What can you tell me about the Dynamite® crape myrtles?
A: Dynamite ® crape myrtles are the red flowering plants. So dramatic and beautiful, they have become a favorite in the landscape since the late 1990s. The original Dynamite ® (trademarked as Whit II) tree grows to over 12 feet tall but there are dwarf varieties which only get to about 4 feet tall such as Petite Red Imp™, Monimp™, and Tightwad Red®, Whit V™ and Victor. Other crape myrtle trees with red flowers can grow to heights of 4 to 10 feet such as Cheyenne (from the U.S. National Arboretum), Christiana which flowers earlier than most other selections, Siren Red® with the trademarked name of Whit VII and Tonto. Other red flowering crape myrtle trees growing over 12 feet tall are Arapaho (from the U.S. National Arboretum), Centennial Spirit, Red Rocket® (trademarked name of Whit IV). Some of these varieties may provide us with better disease resistance – especially those from the National Arboretum. For more complete information look over the University of Florida publication on red crape myrtles: http://edis.ifas.ufl.edu/ep256
Q: I have spotted leaves all over my crape myrtle. What could be wrong?
A: After looking at your photos and examining the samples of your leaves, I believe the spots are caused by a fungus called Cercospora lythracearum as it is the most common fungal leaf spot on Lagerstroemia indica (crape myrtles). In Florida the leaf spot disease was severe in 1976, especially on the pink-flowering variety 'Near East'. Of the 3 flowering varieties utilized in landscape plantings in Gainesville, it was noted that 'Near East' was the most susceptible in terms of greatest leaf infection and defoliation. The red or lavender variety was less susceptible, and the white flowering variety or 'Far East' least susceptible with only a very few Cercospora lesions on the leaves. Heavy infections with Cercospora can cause severe defoliation with a debilitating effect on the plant. The leaf spots caused by this fungus are dark brown, irregular, with no yellow margin. Spotted leaves can become distorted, losing their flat, smooth appearance, particularly as the spots become larger. Leaf spots on the lower surface of the leaves are initiated as tiny brown flecks with no visible spotting on the upper surface of the leaves. As leaf spots enlarge, they appear on both sides of the leaf causing the leaf to turn yellow. The brown spots remain with a green border of leaf tissue, which stands out in sharp contrast to the yellowed leaf. At this stage heavy defoliation occurs. Sanitation is perhaps the most important tool in disease management. Be sure to remove and destroy these leaves to help prevent future infections and disease outbreaks. Another important cultural practice includes surface watering. Because moisture on the leaves allow disease spores to germinate, avoid getting the leaves wet with overhead irrigation. Also be sure to apply enough nitrogen to maintain a moderate growth rate but too much can cause other issues. It is also helpful if your plants are not crowded. Good air circulation permits the leaves to dry quickly after a rain, which helps prevent leaf spot diseases. Use a fungicide made specifically for ornamental plants and alter the type used to avoid building up a resistance. For effective control of Cercospora leaf spot with a fungicide, begin applications when leaves begin to appear in the spring and continue applying a fungicide as needed. Be sure to follow label directions – the label is the law!
Q: Can you give me the names of crape myrtles which are not susceptible to powdery mildew? I am ready to get rid of the tree I now have and replace it because it never looks healthy.
A: The best way to avoid powdery mildew is to plant one of the cultivars bred and selected for resistance to powdery mildew. Additionally, crape myrtle should be planted in sunny locations allowing free air movement so that wet foliage dries quickly. The following cultivars are showing excellent or good resistance to powdery mildew: Semi-dwarf (15 feet) – Acoma (white), Caddo (pink), Hope (blush-white), Pecos (pink), and Tonto (red). Intermediate (up to 20 feet) – Apalachee (orange), Centennial Spirit (dark red), Christiana (deep red), Comanche (coral pink), Hopi (pink), Lipan (red-lavender), Near East (pink), Osage (pink), Osage Blush (pink), Sioux (pink), and Yuma (lavender). Full tree (over 20 feet) – Basham’s Party Pink (lavender pink), Biloxi (pink), Choctaw (pink), Fantasy (white), Kiowa (white), Miami (pink), Muskogee (lavender pink), Natchez (white), Townhouse (white), Tuscarora (coral pink), Tuskegee (pink), Twilight (dark purple), and Wichita (lavender).
One other point I want to discuss is the importance of having a confirmed diagnosis before applying any pesticide. The condition on your crape myrtle is caused by a fungus therefore using insecticides would not be beneficial. The improper application of pesticides means we are not following the guidelines set by the Federal government on the pesticide label. In essence, we are breaking the law. Improper pesticide application wastes time and money and can contribute to the pest resistance. I know it is sometimes difficult to drop specimens by the Extension office but it is essential for us to provide the correct chemical for management. For any of your plant problems attend the free plant clinics at the Yulee office (86026 Pages Dairy Rd., Yulee) – the dates are listed on our website at http://nassau.ifas.ufl.edu. The next plant clinic will be August 6.
Q: My neighbor has a red crape myrtle but she does not remember the name of it. Can you identify the name for me?
A: It is difficult to identify plants down to the cultivar or variety especially when the environment can alter the way a particular characteristic of a tree or shrub will manifest. However, I can give you the name of several red crape myrtle varieties and that should get you started. The red flowering produces blooms throughout the summer into early fall. The first true red crape myrtle was breed and introduced in 1997 by Dr. Carl Whitcomb called Dynamite®. Dr. Whitcomb continued his breeding and later introduced Red Rocket®, Tightwad Red® and Siren Red®, each maturing at a different size than Dynamite®. The U.S. National Arboretum also has an important Lagerstroemia breeding program and recently released red-flowered Arapaho and Cheyenne. A few older selections have long been recognized for their good red flower color, but they never achieved the acclaim and notoriety of these later, improved selections. Thanks to the popularity of Dynamite®, red crape myrtles--new and old--are now very popular and widely available.
Q: What is wrong with my crape myrtle? Some of the limbs are dying and most of the leaves are yellowing and spotting. I remember hearing you say how important is it not to plant trees too deeply and I am sure this tree is planted correctly. What can we do?
A: Since crape myrtles are so hardy it was difficult for me to determine what might be wrong without going out and looking at the tree on site. You were correct, it was not planted too deeply but I was able to see the remains of mushrooms from a root decay called Armillaria. The mushrooms do not last long but they do indicate the decay has spread when the organism starts putting out fruiting bodies (mushrooms). There is no way to chemically remedy this decay of the roots. The damage is done. I would remove the mushrooms immediately, take away mulch from around the base of the tree, and cut all girdling and circling roots. The decay may be only on one side of the tree, but it can and will spread to the other roots and the tree will decline further. More and more of the tree limbs will lose their leaves and limb by limb the tree will go. You can remove the tree immediately but in your instance it is providing some very important shade and unlikely to cause any damage should it fall. Replacing any tree or shrub now, as we are going into the heat of the summer, does not give us the best chance for the plant to become well established. Ultimately, removal of the tree stump and roots will be essential. When taking out the tree, try to remove as much of the soil as possible and replace it with clean soil, well drained soil. Keep the new tree from stress by providing appropriate irrigation during initial planting and establishment period. However, it is also important to not over-water drought tolerant trees and shrubs. Twice a week watering is often too much for woody ornamentals which results in root decay and disease issues. Attached is a publication from the University of Florida explaining more on armillaria: http://hort.ufl.edu/woody/mushrooms.shtml
Q: I continue to have sprouts coming up from the bottom of my crape myrtle. When should I prune them?
A: These sprouts growing around the base of the crape myrtle are called suckers. If you leave them they will eventually become large making the tree have more trunks than desired. We would suggest limiting the crape myrtle to no more than five main trunks with three to five being acceptable. This makes the tree much easier to manage. It is appropriate to prune suckers from any tree any time of year. Removing them early, while the stem is small, is the preferred practice. Remember anytime a pruning cut is made there is the potential opportunity for decay to occur. Therefore, removing the stem when it is small minimizes the possibility for disease. No need to paint the cut with any substance. Allow the natural ability of the tree to seal over the pruned area. Several pruning sessions may be required to control suckers from forming but eventually fewer and fewer will be produced. You may also remove any dead or decaying branches any time of year. Stems rubbing each other, those growing straight up from a branch (water sprouts) or those growing toward the trunk should also be pruned.
Q: Have you ever heard of crape myrtles changing color, i.e. from white to lavender or from lavender to white. This has come up, and I've noticed several crape Myrtle where it looks like someone planted white and lavender in the same hole. It is caused by someone planting more than one seed in the pot?
A: The color change in the flower after it is spent is common on many plants. Finding different colors is rare but there are some plants produce flowers that start out one color and change to another vivid color such as those flowers found on Yesterday, Today and Tomorrow. However, I believe the different colors you are referring to on crape Myrtle are the result of two different cultivars being planted together and that does not occur often. The color of the bloom often does change colors once the flower fades. Sometimes more than one type of crape myrtle is planted together too and you will see various colors of blooms. Planting multiple shrubs together can easily occur especially when you notice that crape myrtles naturally grow as multi-stemmed shrubs. Generally, crape Myrtle shrubs are propagated in nurseries by cuttings because seed propagation takes too long. Therefore, the mixing of two colors would probably be done purposely, which would be a time consuming process for large scale nurseries. Regarding purchasing a plant with only one stem - this plant naturally grows with multiple stems. The University of Florida recommends you keep the number of stems from 3-5 and you will need to work hard to keep the stem numbers that small. Crape Myrtle will put out many more stems than 5 if permitted. We suggest you trim the suckers to limit the stem structure - this will take some vigilence on your part.
Q: After listening to your presentation on trees I realize my crape myrtles, which were planted a few years ago, were planted too deeply. Should I dig them up? They are 15-20 feet tall. In fact, most of what I planted last year is too deep in the ground.
A: At this point it might be best to remove some of the soil from around the root ball area and gradually grade the area around the tree rather than dig up the crape myrtle. If the trees were not receiving enough sun or air circulation I would suggest you dig them up and move them. However, since the only cause of their poor condition is plant depth, I would remove some of the soil. It would probably work best to remove the soil by hand because shovels or hoes could easily damage the root area and potentially introduce disease. Look for the top main root and keep the soil a just above that main root. If suckers have started to form from that main root, break or cut them off. Add 2-3 inches of mulch outside the root ball area. The mulch does not compact as readily as soil and therefore will allow air to reach the roots.
Q: I bought what I thought was an immature lipan crape myrtle (about 3 feet tall) and planted it in April, when it didn't have any blooms. Last month, I noticed white blooms on a few branches. I was shocked, given the time of year and the fact that the blooms are supposed to be lavender. Could this still be a Lipan, or is a tag/label mix-up the likely explanation?
A: The University of Florida has no specific information about this cultivar, although we have done extensive research on crape myrtle. I looked this cultivar up on the internet and according to the U. S. National Arboretum, Lagerstroemia indica X fauriei 'Lipan' produces lavender flowers with white to beige bark, so your tree may have been incorrectly labeled. Its height range is 13 to 20 feet and blooms mid-July through September. This particular variety is also resistant to powdery mildew. You may want to call the nursery where you purchased the shrub to discuss your options.
Q: I have a crape myrtle that has leaves with brown tips; they look like they have been dipped in chocolate. I haven’t put any fertilizer on them but I water them every morning at 2am for about 20 minutes. What could be wrong?
A: Burned edges of leaves can be caused by several things including too much fertilizer, lack of water, root diseases or too much water. I suspect the problem is directly related to the amount of water your crape myrtle is receiving. Crape Myrtle (Lagerstroemia indica) requires full sun, well-drained soils and it is drought tolerant. The damage on the current leaves is permanent but stop watering and any new growth should be fine. However, if the roots have been damaged or root rot exists then the problem will persist. Few, if any, landscape plants require water every day and once trees or shrubs have reached maturity, water them only as needed. In addition, consider retiming your irrigation system to start watering other plants or grass later in the morning around 5 or 6am to avoid potential fungal disease development.
Q: I am very concerned about several trees on my property. I just moved here and have never had to care for a yard. The bark is peeling and the color underneath is orange. Is this caused by a fungus?
A: I am so glad you called me before you treated the trees with a fungicide. I am familiar with crape myrtles and river birches. Both of these trees normally shed their bark and in fact, are prized for the coloration revealed once the bark is shed. These trees are deciduous, which means they drop all their leaves during the cooler months. The variation in colors of their bark makes them interesting once the leaves are totally gone. We can grow several other trees which have unusual bark characteristics such as the Sycamore. The bark on sycamore trees may be very white or appear as variations of green and cream giving it a “camouflage” pattern. Perhaps you are fortune enough to have a Sweet Gum Tree or Winged Elm with the corky growths along the twigs and stems. The Hercules-club tree, also known the Toothache Tree, has cone-shaped spines on the trunk. You might consider taking a nature hike at Ft. Clinch on Amelia Island to see one of these trees – well worth the small entrance fee.
Q: You added a swamp dogwood to your demonstration garden this year. I have never heard of this tree. Please give me more information.
A: Swamp dogwood, Cornus foemina is found frequently throughout Florida's wet hammocks, along the edges of swamps and floodplain forests. It grows to 15 feet high, with stiff, upright branches, reddish-purplish stems; dark green leaves which are 1 to 4 inches long. The creamy white flowers bloom in a cluster measuring up to 3 inches across. The fruit turn blue once they mature in the fall. Typical of most dogwood plants, this shrub is deciduous and drops its leaves in the fall. It should be planted in partially shady sites in well-drained, moist areas but not in continually wet soil. It prefers slightly acidic soil.
Q: I am able to get a Florida dogwood and I wanted to be sure it would grow here. I have filtered light and a slightly moist soil condition.
A: The Florida Dogwood, Cornus florida, would be a great choice since you are purchasing it from a local plant nursery. This means it was most likely grown here in Florida. Filtered light is perfect and the sandy soil is not a problem although h the soil should be well-drained. It is important to allow for enough room for this lovely tree as it can grow up to 35 feet tall and spread to almost 30 feet. When planting, remember not to amend the hole, which means – do not add heavy organic matter like Black Kow, fertilizer or other typical amendments. Slice into the root ball to get rid of circling roots, loosen the soil in the area where planting 2 - 3 times the size of the root ball. Fill the hole with surrounding soil 2/3 of the way, then fill with water, tamp down then fill in the rest of the hole with native soil. Do not plant this tree too deeply; the top roots should have only about 1-2 inches of soil on top. Build a berm around the root ball and mulch outside the berm with pine bark or pine straw. Watering is essential – so read the attached publication on irrigation to establish trees: https://edis.ifas.ufl.edu/pdffiles/EP/EP11300.pdf
Avoid pruning the canopy except for broken limbs, crossing or rubbing limbs and/or to give the tree better structure. The attached publication is more complete information about the dogwood tree.
Q: I want to use the seed from my dogwood tree to propagate other dogwoods. Can I do that?
A: You have posed a very good question. The quick answer is yes, you can propagate the seeds and they should produce dogwoods. Since we are entering into the fall and winter season you should protect the tender growth from the cold until warmer spring weather. Dogwoods, like roses and citrus, are often grafted onto hardy root stock. The graft is selected for various reasons such as large foliage or disease resistance. The seeds you have may not produce the strong, virile specimen now present in your landscape. In order to have the identical specimen you would need to take a cutting and propagate it, which is easy to do. However, half the fun of propagating from seed is growing something from infancy – so go ahead and try it and enjoy the possibilities.
Q: My neighbor has a juniper tree which has blue berries on it. Why I don’t see these berries on other similar trees? Is it a special variety?
A: I am impressed with your power of observation. I believe you are looking at the female tree of the Eastern Red cedar tree, Juniperus virginiana. The reason you are not seeing the fruit on the other trees as these trees have male and female trees. The females bear the fruit while the male trees produce pollen. Red cedar trees are evergreen reaching heights upward to 50 feet which spread 8 to 15 feet when grown in a sunny location. The fruit is a blue berry on female trees and they are very showy when the production is heavy. The fruit is strikingly beautiful against the dark green leaves. The fruit provide food for wild birds when winter food is limited. The tree is highly drought and salt tolerant; it is not finicky about soil types. The shape of the tree develops best when grown in full sun but it will survive partial shade as I have a volunteer tree in my back yard growing in partial shade. Eastern Red cedars are difficult to transplant due to a coarse root system, except when quite small. There are a handful of cultivars to choose from and most reputable plant nurseries would be able obtain them upon request. For more complete information check out the website from the University of Florida publication on the tree: http://edis.ifas.ufl.edu/st327
Q: What kind of tree is this? It puts out hundreds of seeds.
A: I am glad you brought in a clipping of the tree with the seeds as it made it much easier to identify. I believe you probably have a Chinese Elm. A fast-growing, deciduous or evergreen tree, Chinese Elm forms a graceful, upright, rounded canopy of long, arching, and somewhat weeping branches which are clothed with two to three-inch-long, shiny, dark green, leathery leaves. Here, in the southern extent of its range the tree remains evergreen. The bark naturally sheds which many people often mistake for disease, but can provide an interesting pattern on the trunk making it more attractive. Chinese Elm can reach 80 feet in height but is more often seen at 40 to 50 feet, making it an ideal shade, specimen, street or parking lot tree. The root system is comprised of several very large-diameter roots which can grow to great distances from the trunk. These are usually located fairly close to the surface of the soil and can occasionally lift sidewalks. They can also get into sewer lines causing damage, but they are usually not a serious problem. Consider planting far away from sidewalks and drain fields. http://edis.ifas.ufl.edu/st652
Q: My elm tree has dropped hundreds its tips and they are all under the canopy. What could be causing this?
A: This is a common question during the fall from both homeowners and commercial sites – no one is immune. More than likely it is the result of a long-horned beetle called a twig girdler. Twig girdlers are important long-horned beetles. The grayish-brown adult females (1 1/16 inch long) are active from September to November. Twig girdlers are difficult to spot on the bark of trees as they have perfect camouflage coloring. The hard outer wing coverings may display interesting and distinct patterns. Their damage occurs primarily from egg laying. They girdle limbs by chewing a V-shaped groove entirely around twigs, branches or terminals.
Eggs are inserted into the bark on the girdled part of the branch away from the tree. Girdled limbs eventually break and fall to the ground. This is the reason you have seen so many small branches cut off and lying on the ground. Larvae cannot develop in healthy sapwood. Damage can disfigure a young tree and leads to secondary branching, especially if the terminal is attacked. Oak, persimmon, hickory and pecan are common hosts. The best control method is to pick up the small branches which have fallen to the ground, bag or burn them. If you have a young budding entomologist at home, they could leave some of the twigs in the shade and cut into the wood every week or so to measure the growth in the larva. Ultimately, they may be able to see a full grown adult. Be sure to have a camera ready to document each event and use the metric system when taking measurements. This would make a great classroom project. Attached is a website with other information on a variety of tree borings commonly found in Florida. http://edis.ifas.ufl.edu/mg007
Q: My elm trees are not doing well. I am seeing some limbs die at the top. My cat has been known to scratch the bark from time to time. Would that cause any problems?
A: Elms, crape myrtles, fruit trees and several others are thin barked trees and therefore easily susceptible to trunk damage. Hardwood trees develop their vascular systems and growth tissue a ring just inside the bark. When this bark is damaged it permanently diminishes the trees ability to produce new tissue and transport water, minerals and food to other parts of the tree. However, the tree may be able to survive on the remaining undamaged tissue. If enough damage has been done, especially if it has occurred completely around the tree, it is possible to lose the whole tree. Nothing can be done to the tree that has already been damaged but if this is a habit of “Fluffy’s” then protecting this and other trees from further damage is important. We do not recommend you use any pruning paint or attempt to cover the scratches as this may seal in fungal spores and cause even more damage. Take a “wait and see” attitude and hope for the best. Maybe “Fluffy” could use an outdoor scratching post made of carpet as a substitute tree as this scratching behavior is innate.
Q: I hope you can help me. I recently transplanted three small Drake Elm trees that came up in my mother's flower beds from an older established Drake Elm she has in her yard. The small trees had already started sprouting leaves when they were transplanted. After about a week of transplant the new leaves started drying up and eventually fell off. It's been approximately 6 weeks since the transplanting took place. The trees only have about 3 to 4 very small leaves on them; the bark is green at the base and at the tips of the branches. The questions are: Did the trees go through a shock? Will new leaves grow eventually? Should I use any root stimulator or fertilizer to promote leaf growth? How long should I wait before I consider them defeated? Your help is greatly appreciated!
A: The trees may have indeed gone through a shock, however since the tree bark and branches are still green, the leaves may eventually return. The most important thing about transplanting trees or shrubs is to water them. Hopefully you have been watering the shrubs for the last 6 weeks, if not, then some root damage has probably already occurred. I would discourage you from using any fertilizer or soil amendments. Right now the focus and energy of the plant should be on developing roots and water is the best way to ensure that. Of course over-watering can cause problems too. I have attached Dr. Ed Gilman's website, professor from University of Florida, which discusses transplanting of trees and shrubs - that information should help you get your elms back on track. Click on any of the sites and get more specific information. Be sure to check out the irrigation info since it tells of how much water is needed depending on how large the tree is. Good luck.
Q: My eucalyptus tree is dying from the bottom up. I water it once a week. What could be wrong?
A: You most likely have one of the cultivars of Eucalyptus globulus which is not native to this country. It prefers well drained, acid soils. I suspect with all the rain we have been receiving and the once a week watering, this tree has developed a root decay from which it cannot recover. There is no chemical fix for a root rot and the tree will probably slowly decline until it dies. There are a few things you could do to possibly slow the process. Remove any mulch from around the root area, check for girdling or circling roots, cut and remove them. Remove any excess soil from around the roots – they should have only an inch or two of soil on top. Eucalyptus trees prefer a less humid environment found in most parts of California – very different from what we experience here in Northeast Florida. Remember, most trees and shrubs do not require weekly irrigation unless we are going through a severe drought. Whenever possible, irrigate flower beds, trees and shrubs separately from lawns as their needs are vastly different.
Q: I moved here a few years ago and I love all the variety of plants and trees around the area. However, I miss the gingko tree from my home town. Why don’t I see more of it growing here?
A: I love the ginkgo tree, Ginkgo biloba, too; especially the yellow fall foliage and the unique shape of the leaves. It has no serious insect or disease issues which would make it a wonderful tree in a landscape. This particular tree, however, prefers to grow in more northern climates, where it is exposed to fewer hot and humid days. Although I have seen it as far south as Central Florida, it never flourishes like it does in areas north of cold hardiness zone 9. Gingko trees tolerate most any type of soil, most any type of light conditions and they are fairly drought tolerant. It is relatively disease free but it is important to select only male trees as the females produce fruit which put off a disgusting and offensive odor. In addition, fruit drop can be very messy. Too many commercial sites have selected the wrong plant and ended up years later with messy, female trees. According to the University of Florida, select a grafted male plant by purchasing a specific cultivar such as `Autumn Gold', ` Fastigiata', `Princeton Sentry', or `Lakeview'. If the plant is propagated by seed, it could take as long as 20 years or more for Ginkgo to fruit and then it is too late. `Autumn Gold' has a bright gold fall color and rapid growth rate. `Fastigiata' has an upright growth. `Princeton Sentry' has a narrow conical crown for restricted overhead spaces, which works well on commercial sites but can reach heights up to 65 feet. `Lakeview' has a compact, broad conical form. http://edis.ifas.ufl.edu/st273
Golden Rain Tree
Q: What is the name of the tree with the salmon colored seed pods? It is so pretty, I just love it.
A: While it is true that this tree is beautiful it is also considered a pest tree. Golden rain tree, Koelreuteria elegans, is native of Taiwan and it has become a very popular landscape tree because of its colorful yellow petals and rose colored fruit capsules. Even though this tree is loved and valued by many, we cannot ignore the invasive characteristics which initiated its appointment as a Category II exotic invasive. Koelreuteria is a fast growing plant able to grow in an array of environmental conditions. Golden rain tree seeds are thought to be spread by birds and have the capability of germinating as quickly as 6-8 days. It is a deciduous tree that grows 25 to 50 feet in height, with a 35 to 50 foot diameter spread. Introductions of Koelreuteria as an ornamental tree have made it possible for this tree to escape from cultivation and naturalize in Texas, Louisiana, Alabama, and Florida. Because it is a fast grower and has greater seed viability in warmer climates, Golden rain tree has the ability to crowd out desired native species which means it can and does completely alter the local landscape. It is best for us to refrain from purchasing, propagating, or planting Golden rain tree due to its ability to escape into natural areas
Q: What can you tell me about a tree that produces small, red or yellow fruit like an apple but it is called a “Haw” tree?
A: This tree is often called several other common names such as “May Haw”, “May Hawthorne”, or “Apple Haw” but its scientific name is Crataegus aestivalis. The May Hawthorne is part of the rose family therefore it will have thorns on the branches, so be careful when gathering fruit. This slow-growing native North American tree reaches a height of 30 feet that spreads to 35 feet or more. The dark green, deciduous leaves are often three-lobed and have red/brown undersides. The leaves display no appreciable fall color. The white, showy springtime flowers appear before the new leaves unfurl and are followed by the production of one-inch red fruits. Although the sweet tasting fruit can be eaten, it does not attract wildlife. May Hawthorne can grow in full sun to partial shade, a variety of soil conditions, and has very few disease or pest problems.
Q: My neighbors have a thorny tree growing out
of their pear tree. It is growing quite large and we want to
know if it is a wild pear or plum.
A: The specimen you brought to the office appears to be one of the hawthorns, Crataegus. However, it is not the same variety of Indian Hawthorn most of us are accustomed to seeing in our landscapes. The picture I have included is a member of the Crataegus family. This plant could possibly overtake the pear tree and choke it out by girdling the trunk of the pear tree. It would be best to remove as much of it as possible. Cut it down as close to the root as possible, be careful not to cut into the bark of the pear tree. An herbicide such as glyphosate (Round-up) should be painted on the stump immediately to discourage suckers from forming. The flowers are probably similar to the pear flowers and therefore it has gone undetected for a long time.
Q: What are these growths on my pignut hickory leaves? I think they are insects and they are chewing my leaves.
A: I appreciate you bringing in samples of the growths as this helped me identify the problem more easily. Actually, these growths are most likely an insect gall. Galls are formed when the female insect places an egg in the leaf tissue and then the plant forms a protective coating around the egg. The egg then goes through its normal growth stage from egg to larvae then pupae exits out of the gall as an adult. Generally, these galls cause few problems for the plant and in some instances, the galls support beneficial insects. I believe the chewing you are seeing on the leaf edges is caused instead by a caterpillar such as the eastern tent caterpillar. Eastern tent caterpillars can be seen in of our area in April – right now! Just poke holes in the caterpillar webbing and the birds and wasps will take care of the caterpillars for you.
Q: My large holly tree fell over after the storm, can it be saved?
A: Only trees recently planted or have a trunk diameter smaller than 4 inches should be staked or replanted if they have fallen over during a storm. Large or older trees need to be removed as they were most likely compromised anyway. If the tree is small enough, prop it back up and do the following: Keep roots moist but not wet. If the hole is holding water, this might not be the best site for the tree – consider moving it to another area. Trees and shrubs grow best in well-drained soil. Be sure the new hole is wide enough to hold the roots but never plant it too deeply. The large roots coming off the trunk should be within the first few inches of soil. Remove any circling/girdling roots while they are exposed. Remember the roots should be going away from the trunk of the tree like the spokes of a wheel. Prune any jagged and torn roots. Set the tree upright and fill the hole with native soil – do not be tempted to add amendments to the hole. Water the soil in as this will remove any air pockets. Good rule is to water with 3 gallons of water per inch of tree diameter. This can be done 3-4 times a week for several weeks until the tree becomes established. In addition, this is NOT the time to add fertilizer. We want the tree to put out new roots only – not new shoots or flowers. It would be best to stake the tree while it is vulnerable but only leave the stakes on for 6-9 months. Be sure the cables do not cut or girdle the tree trunk. Normally, we would not suggest you do any pruning on the tree canopy but remove any cracked or broken limbs at this time. Remember we do not recommend painting over the wound of the tree – allow the tree to heal over the wounds. Keep grass as far away from the tree as possible – a best management practice all the time. Mulch several feet away from the trunk – never allow mulch to touch the trunk of any tree. It may take several months to even a year for the tree to overcome the trauma of the storm. Be patient. Regarding palms – just remove any totally dead or broken fronds. Fertilization should not be done again until March of 2017 using only 8-2-12. Then reapply in June and September.
Q: One of my clients has three East Palatka hollies which have been in the ground for more than eight years. These trees appear to be dying and I am not sure what is causing this. I know the pH of the soil is too high and I have applied a sulfur product but the trees are dropping their leaves suddenly and looking quite weak.
A: I had to look at the site to determine what might be the cause of this problem because this tree is so hardy and has few disease problems.In fact, generally we can point to environmental issues as the main reason this tree fails in the landscape.The tree site contained a large manhole which apparently connected several water and/or sewage drains. I suspect the large hollies had little room to grow around these drain pipes and the area probably contained very little quality soil. I gently hand dug an area around one of the trees approximately one foot deep and 2 feet wide. I noticed the large tree had about ¼ to ½ of its roots missing, which would put it under undue stress. The missing roots were probably cut away long ago to make room for the other shrubs surrounding it. However, the remaining roots were beautiful and healthy so it was easy to eliminate a root rot.In addition, I discovered a few circling roots which was indicative of a declining tree. As I was digging I notice large deposits of lime rock, similar to that used when building roads. It is probably this lime rock that is causing the pH of the soil to remain a high pH. This may also be contributing to the decline of some of the surrounding azaleas in addition to lacking good soil for healthy root and shoot growth. The area surrounding this small bed was impervious hardscape (apartment buildings, sidewalks, parking lots and roadways). The bottom line is that these tree roots probably have no place to breath and grow and removing them may be a better choice. Consider replacing them with a palm that can take a wider range of pH soils and does not have a large woody root system.
Q: I've harvested the berries from an East Palatka Holly plant, can you please tell me the best way to germinate the seeds. Thank you.
A: The publication I have attached is the best one I have seen on seed propagation which is from the North Carolina State University by Extension Agent Erv Evans and Professor Frank A. Blazich. Near the bottom of the publication is a table with different types of plants and hollies are on the list. It is important to note, propagation from seed, which it can be richly rewarding, may not give you the exact same characteristics of the mother plant. It is possible to end up with something even more spectacular or it may be less showy, or not as disease resistant, etc. If you are willing to wait in the hope of producing that one fabulous tree, then I say go for it. However, if the idea was to get duplicates of the mother plant, then cuttings would be a much better choice. In addition, you will not have to wait as long to get a small tree as a plant grown from seed. Growing the tree from seed may take years longer and possibly produce a tree with less desirable characteristics. In addition, you may purchase a mature holly tree from one of the local plant nurseries at a fairly reasonable cost. This publication goes into great detail and should be beneficial to any home gardener. http://www.ces.ncsu.edu/hil/hil-8704.html
Q: What can you tell me about the Japanese blueberry tree and can I grow it here?
A: Japanese blueberry, Elaeocarpus decipens, can be grown in our cold hardiness zone. This evergreen tree grows about 30 to 40 feet tall and equally as wide. Japanese blueberry prefers well drained soil and full sun. Some interior foliage turns bright red and drops in spring and periodically throughout the year. This is normal and is not cause for concern. Japanese blueberry has small, inconspicuous fragrant flowers. It has a propensity to become chlorotic on high pH soils so this might limit using it in commercial or home sites where soil is often alkaline. It is too difficult to lower the pH for any substantial amount of time to keep the plant lush and green in an alkaline environment. The high production of fruit may cause it to be messy on walkways. However, berry production should not be a problem if using it as a hedge in a home landscape. Just keep its shrub away from driveways and sidewalks. Piercing sucking insects may be a problem, but early scouting of insect feeding can be controlled with either insecticidal soap or ultrafine horticulture oil. Formation of sooty mold is your best indication the pest populations have become too high
Q: I have notice a few commercial and governmental sites in Central Florida have been using Jerusalem Thorn as a parking lot tree. Why don’t we use it more often here? It seems like a care-free tree.
A: Usually the biggest deterrent to using new or different trees in commercial and government sites is because these areas are often regulated by local ordinances which can be difficult to change or alter. In addition, availability of tree varieties is often very limited by the nursery growers stock. Growers want to produce what will sell (which is why they are in the nursery business) and unusual trees can be very risky. The only other downfall of this particular tree may be its short life span which is only 15-20 years. However, most of us know trees in urban areas are not long-lived anyway because urban environments are often extremely severe. The Jerusalem Thorn tree will tolerate very hot and dry conditions which would make it a great median or parking lot tree. This tree has strong wood and with its natural open shape allows it to tolerate high winds well. For the reasons stated above, it would be a good addition to some commercial sites but it should not be planted in an area which would be receiving irrigation twice a week, which often occurs in lawn grass landscapes. Attached is a publication from the University of Florida on the Jerusalem Thorn: http://edis.ifas.ufl.edu/st431 Photo from Berkley
Q: I was out of town for a few weeks and upon my return I notice my magnolia was totally dead. What happened?
A: I am only able to speculate the cause of death since I am examining a small clipping from the tree. However, I noticed a large portion of the bark was missing from the limb you brought to the office. Although I did find scale insects they were not in numbers large enough to destroy the whole tree. I suspect the tree either took direct hit from lightening or the strike was nearby. Nothing ends the life of a tree as quickly as the intense energy exerted upon it by lightening. A direct hit from lightening will often cause the bark to be blown off similar to what happened to your tree. The removal of this much bark would cause the demise of any tree. I do not believe the bark removal was from an animal or machinery as I see no teeth impressions or machine made marks. There are ways to redirect lightening from important specimen trees but you will need to contract a tree company which employs certified arborists to help you correctly install proper lightening rods. There are lists of certified arborist for our area at the Florida Chapter of the International Society of Arboriculture at: http://www.isa-arbor.com/findArborist/verifyArbByLoc.aspx Type in the closest city which could be Fernandina Beach, Callahan or Jacksonville. Although I am listed as a certified arborist under the City of Callahan, I do not install lightening rods! Sadly, the tree ultimately will need to be removed.
Q: I 'm going crazy trying to identify a tree that is blooming in Nassau County right now. The tree is wild and has blossoms of 5 creamy white petals, and tiny blossom berries.
A: The tree you are referring to is probably the Loblolly Bay, Gordonia lasianthus. Loblolly Bays are native to America and found throughout the southern part of the United States. This tree is an evergreen reaching heights up sixty feet but spreads only to about 15 feet. Because of the small spreading growth of this tree it would be a good choice for our smaller landscapes in urban areas. This tree grows in all light conditions, prefers acidic soil and can tolerate some occasional flooding. If it is grown in full sun it will require moderate irrigation to keep soil moist. This additional moisture requirement is not usually a problem if Loblolly Bay is sharing space with lawn grass. Loblolly Bay would be a good choice for boggy areas although it is not salt tolerant. It requires little or no pruning to maintain a central, strong trunk leader. It can be propagated by seeds or cuttings. Borers can weaken the tree and occasionally aphids may be a problem but it has no disease issues. Gordonia lasianthus ‘Varigata’ is a variegated cultivar of Loblolly Bay with green and white leaves and white flowers.
Q: My loquat tree is looking terrible. The ends of the branches look burned and it is dropping its leaves. What is wrong?
A: The loquat tree, Eriobotrya japonica, is a beautiful Japanese plum tree which can reach heights up to 25 feet. The plums are about 2 inches in size, are edible and for best results should remain on the tree to ripen. The fruit appears anywhere from February to April and they should be thinned to improve on fruit size. The tree can be propagated by seed but it usually produces inferior fruit therefore cuttings provide the best specimen tree. They grow in a wide variety of well-drained soils but are not truly salt tolerant. The loquat requires no pruning. I suspect the problem with your tree is a disease called fire-blight. You can attempt to prune out the disease, which is caused by a bacteria, but you must be very careful about cleaning your pruning utensil between each pruning cut. Pour 10 cups of water to 1 cup of bleach into a bucket, dip the blades in the solution and wipe your blades then make your cut, repeat after each cut (dip, wipe, and snip!). Make your cut 4-6 inches below the damaged stem or branch. If your tree does not recover consider digging it up and burning it. Do not plant a loquat tree again in that area. This bacteria is easily transmitted from branch to branch even by insects, so don’t feel badly if you are unable to “cure” this tree.
Q: What is wrong with my loquat? Some of the branches are dying from the tips and the fruit is dried up and dead.
A: Your loquat has a disease called fire blight, which is caused by bacterium (Erwinia amylovora), it can spread rapidly, killing individual apple and pear trees when conditions are right for disease development and susceptible root stocks are used. The first symptoms of fire blight occur in early spring, when temperatures are above 60 °F and the weather is rainy or humid. Infected flowers turn black and die. The disease moves down the branch, resulting in death of young twigs, which blacken and curl over, giving the appearance of a “shepherd’s crook.” Leaves on affected branches wilt, blacken and remain attached to the plant, giving it a fire-scorched appearance. Slightly sunken areas, called cankers, appear on branches and the main stem. Many parts of the plant can be affected including blossoms, stems, leaves and fruit. During wet weather you may notice a milky-like, sticky liquid oozing from infected plant parts. Insects and rain can spread the disease. Some ornamental pear trees, such as ‘Bradford,’ are considered resistant to the disease but can become infected when conditions are favorable for disease development. Certain plants in the rose family (Rosaceae), including many ornamental plants, can be affected by fire blight. Some of these include crabapple, pyracantha, hawthorn, photinia, quince, mountain ash, loquat and spirea. Reduce the spread of fire blight by removing and destroying all infected plant parts. Pruning cuts should be made 12 to18 inches below any sign of infected tissue. Disinfect all pruning tools between cuts using a solution of 1 part household bleach to 9 parts water. Succulent new growth is easily infected, if injured. Avoid excess nitrogen fertilization which results in excess succulent growth.
Q: I want to replace the Redbay trees which have died recently in my landscape. What would be a suitable tree?
A: You might consider planting Magnolia virginiana, Sweetbay magnolia or Swamp magnolia. When crushing leaves, it emanates a spicy fragrance similar to the Redbay leaf. Unlike the Redbay, Sweetbay magnolia leaves should not be used for cooking or seasoning. It is not evergreen, like so many of its cousins, so you should be prepared to rake leaves in the fall. Sweetbay magnolia prefers moist, acid soil and is often found along roadsides in our area. It is easy to recognize Sweetbay magnolia even from a distance as the silvery, colored underside of the leaves show up in the wind. The tree produces creamy, lightly scented flowers throughout the summer and early fall. It can reach heights of up to 60 feet so be sure you allow for the height. For those interested in attracting wildlife, the fruit provides food for birds and squirrels. The bark on Sweetbay magnolia is thin so it is important to keep this tree away from mower blades or string weed cutters as the tree can be easily damaged. As with any tree, keep lawn grass as far away as possible. A couple of inches of mulch under the canopy spread out to the drip line (under the branches) will help keep weeds down and moisture in around the roots. Be sure to keep the mulch away from the trunk of any tree or shrub – no mulch volcanoes! Sweetbay magnolia is a native tree and found throughout most of the United States. The photo is from Vanderbilt University.
Q: What can you tell me about the trees which produce the big, beautiful pink or purple flowers? One of my neighbors called it a tulip tree. Do you know what it is?
A: This is another example where using a common name fail us. The state tree of Indiana is called a Yellow poplar, or Tuliptree, Liriodendron tulipifera, but I am pretty sure you are not talking about this stately beauty. Its flowers are a creamy, yellow. We can grow this tree in our area but the flower color is not correct. I believe you are asking about the Tulip Magnolia or Saucer Magnolia, Magnolia X soulangeana. Unlike some of its evergreen cousins, this magnolia is deciduous. The beautiful flowers appear before the leaf is formed. It can reach heights up to 25 feet with a 15-20 foot spread. So be sure there is enough room in your landscape before making it a permanent addition to your yard. Some of the flowers of certain cultivars have a lovely, faint fragrance. The flowers can be quite large ranging from 5 – 10 inches in diameter and come in white, purple and pink. They can be grown in full sun to part shade and prefer a well-drained, moist soil. They have no serious pest problems. Saucer magnolia trees can be grown as far south as cold hardiness zone 9. This tree has become such a favorite for gardeners it can be found at many of the retail garden centers. Photo is from University of Georgia.
Q: I was told when I purchased my “Little Gem” magnolia that it was a dwarf variety, but this tree is getting bigger and bigger. How tall and wide will it eventually get? I am already having difficulty walking around my sidewalk.
A: The standard Southern Magnolia, Magnolia grandiflora, can reach heights to of 80 feet with a spread of 30 to 40 feet. These trees are native to North America and are absolutely magnificent specimens but they also need plenty of room to grow. ‘Little Gem’ is a dwarf cultivar of the Southern Magnolia and it can potentially grow to heights of 25-30 feet with a spread of 10 to 12 feet. Another advantage the ‘Little Gem’, besides size, is it flowers within two to three years whereas the parent may take up to twelve years to produce flowers. However, ‘Little Gem’ is still a large tree unless you compare it to the parent. If your site does not have enough room to accommodate the ‘Little Gem’ consider moving it to another site and select another tree. It is probably not the best choice for planting too close to sidewalks, driveways or underneath eaves once you know its potential height and spread. If you need to choose another smaller tree, consider one of the dwarf crape myrtles – some are as small as 8 to 10 feet tall.
Q: I am upset because my magnolia is dropping leaves although it seems to be putting out plenty of flowers. All the leaves are not dropping but it does seem to be losing more than normal. Should I be worried?
A: It takes a lot of energy for trees and shrubs to flower which often causes the plant to drop some of its leaves. Magnolias are notorious for leaf drop just before flowering. It is especially noticeable on evergreen trees that produce large leaves and create a mess when numerous leaves appear to drop at one time. This is not something you need to worry about since the tree will put out new leaves once the flowering process has ended. However, if most or all of the leaves drop then we should look at some other causes and truly be concerned about the overall health of the tree. This might be a good time to lightly mulch the area underneath the magnolia with pine straw or pine bark to ensure the soil does not become too compacted. Compacted soil limits the amount of oxygen to the root area and can cause serious problems for trees and shrubs. Mulching this area will also help keep the weed populations down and improve the overall look of the barren area under the tree.
Q: What is wrong with my magnolia tree? It is very large but some limbs are dying and the leaves are yellowing between the veins?
A: After exchanging some phone calls and looking at a few photos I didn’t feel any closer to determining what was wrong with the magnolia until I had branch specimens. My initial thought was something might be wrong at the root area. We tested the soil pH and discovered it was alkaline near 7.3, but that didn’t completely explain why the tree was struggling. If the soil pH is too alkaline the root systems of plants cannot absorb some of the essential nutrients and it will often show up in the yellowing leaves. It is best not to add lime to Florida landscapes unless a soil analysis indicates it is needed. Since 2-3 inches of organic mulch is all that trees or shrubs require, removal of the extra mulch was beneficial. Always keep mulch away from the trunk area of trees and shrubs. Avoid building “mulch volcanoes” as this can contribute to stem and root rot. Removal of competing lawn grass from the root area was also important. However, part of the mystery was solved when I examined some of the magnolia limbs and discovered carpenter ants had bored into the vascular tissue of the limbs. Carpenter ants were also discovered at the base of the tree once the excess mulch was removed. One important thing to note is carpenter ants generally go into trees that are already in decline or stressed. Will the tree recover? It might be worth trying, but all our efforts may not be able to bring the tree back to complete health. The dead limbs need to be removed immediately. If the root and lower trunk area indicated rot then it is time to think about taking the whole tree down.
Q: What are the big, red trees I see blooming right now?
A: The beautiful, large, red trees you see
now are maples.
The red maples are among the most common trees found on moist or wet soil in our county. The flowers and papery fruit occurred in early late winter or early spring before leaves break out. The winged fruit range in color from scarlet to brownish-red to even straw colored and are very showy.
Q: I am considering planting some red maples in my yard. How far away from the house should I plant them?
A: There are several varieties of red maple, Acer rubrum, which grow well in this area. Red maples grow in full sun to partial shade and provide excellent shade in the summer as well as beautiful fall color when the leaves change. They can adapt to dry or damp sites but they cannot tolerate salt air or brackish water. Red maples have shallow root systems and are fast growers. If they are planted in high alkaline soil (high pH) they may show signs of yellowing leaves. Red maples have the potential for reaching heights of 130 feet but are most often found 35-50 feet tall here. The limb spread can be up to 35 feet. Therefore, I would suggest planting the maple on your property to allow for plenty of room for height and limb growth. A common mistake made by many homeowners is to not consider the mature height and spread of a tree or shrub. This ultimately means an unhappy plant and homeowner. You are wise to think about the mature size of the tree before making your selection.
Q: I see the maples are bursting with color right now. After looking closely, I noticed a pair of seeds. What are they?
A: The botanical term for these structures containing the maple seeds is samaras, but they are more often referred to as “helicopters,” or “whirligigs.” All maple trees produce samaras, but red, silver and Norway maples often produce the largest quantities. Over the next few weeks, these seeds will rain down on lawns, decks, roofs and gutters in many locations which can become a nuisance, especially after we have had such a large number of laurel oak leaf drop within the last few weeks. But raking leaves from the yard and removing them from our gutters in the spring is a small price to pay for having such large, beautiful trees on our property. Both oaks and maples are also the source of much of the yellow pollen we are seeing all over our cars lately, in addition to being the reason for our allergic reactions to pollen. It is possible to take the seeds and propagate your own maple tree. Red maple trees are incredibly fast growers so you should have a nice size tree within a few years. Seed propagation would be a wonderful project for any young person. Nothing is more rewarding than seeing a tree develop from seed.
Q: My neighbor is planting a trident maple in his yard. Isn’t that the same thing as a red maple?
A: No, the two maples are different species. The red maple is Acer rubrum while the Trident maple is Acer buergeranum. Notice the first name, which is the genus, is the same as this identifies all maples. However, the last name, which identifies the species, is quite different. They are both deciduous, tolerate occasional dampness and grow well in this area. The leaves of the Trident maple are distinct as they have only three lobes whereas the red maple has multiple lobes. Trident maples can grow to about 45-feet tall with about a 25 foot spread. The leaves are glossy green above and paler underneath, which turn various shades of red, orange, and yellow in autumn. Flowers are bright yellow and showy in the spring. Typically Trident maples are found multi-stemmed but they can be trained to have only one central trunk. Red maples are fast growing whereas Trident maples grow at a moderate rate. In addition, the bark of the Trident maple is orange-brown which adds winter interest once all the leaves drop. Trident maples make good patio specimens if space is limited and are often used as bonsai plants. Trident maple should be planted in full sun or partial shade on any well-drained, acid soil and is quite tolerant of salt, air pollution, wind, and drought. Like other maples, some chlorosis can develop in soils with pH over 7 but it is moderately tolerant of soil salt. It performs well in urban areas where soils are often poor and compacted. Trees are easily transplanted due to their shallow root system and are fairly 'clean' trees since they do not drop messy leaves, fruit or flowers. Several cultivars are known, with trees having dwarf growth, corky bark, variegated leaves, and a variety of leaf shapes. Some particularly good cultivars include: 'Akebono', 'Goshiki Kaede', 'Maruba', and 'Mino Yatsubusa'. They have not been tested extensively in urban areas and will probably be difficult to find. For more information please check out the University of Florida publication: http://edis.ifas.ufl.edu/st009
Q: My children bought me a Norfolk Island pine for Christmas. I want to plant it outside but my husband thinks it would be better suited in a protected area like our screened patio. It really did not come with any type of watering instructions. What can you tell me about it?
A: This is a very pretty plant and is seen growing outside in many areas of South Florida. In fact, we have a few growing right here in Northeast Florida along the coast. It is not a plant I would recommend putting outside because of the chance of freeze damage, but there are always special warm pockets in the area where the plant could do well. The scientific name for Norfolk Island pine is Araucaria heterophylla. It is native to Norfolk Island in the South Pacific between Australia and New Zealand. The ideal indoor climate for this species is bright and cool, with daytime temperatures ranging from 60 to 70 degrees and slightly cooler at night. Although the Norfolk Island pine will adapt to bright indirect light, the plant will look its best with a couple of hours of direct sunlight daily. If the light source is coming from just one direction, you'll want to rotate the plant a quarter turn weekly to keep it from tilting toward one side. It is not unusual for leaves on the bottom of the plant to turn brown and drop off, especially when adjusting to a new site and light conditions. However, if large numbers of brown leaves occur on the shrub it often means too much water or root decay. Be sure to plant it in well drained soil and err on the side of less water. It is possible for this plant to reach heights of 200 feet but it more commonly grows up to 80 feet. You might consider initially growing it on the patio just to get it adjusted to the area; then move it outside once it gets too large.
Q: I found these unusual growths on my oak trees. What are they and will it cause my oak tree to die?
A: Thank you for bringing this to the Extension office; I have seen this gall only one other time in my thirteen years of being a Horticulture agent in Nassau County. I believe the gall is called an oak apple gall. Galls occur on a wide variety of plants. These growths may be the result of fungi, bacteria, nematodes or mites, but insects are the prime cause. Gall-forming insects include aphids, phylloxerans, psyllids, midges (gall gnats) and cynipid wasps (gall wasps). Of the more than 2,000 gall-producing insects in the United States, l,500 are either gall gnats or gall wasps. About 80 percent of the gall wasps produce galls specifically on oak trees. In fact, 60 percent of all known insect galls occur in the oak family and 30 percent occur in the daisy, rose and willow families. These growths are called galls because they contain large amounts of tannin, which has a very bitter taste. Long ago, they were known as "gallnuts" because they tasted as bitter as gall. Plant galls are abnormal growths of plant cells formed as a response to the insect's stimulus caused by egg laying, or larvae or nymphs feeding. Galls seem to cause a lot of concern to the general public. Generally they do not seriously harm the plant. Most ornamental plants and trees are not apparently injured even by relatively large numbers of galls. Attached is the publication for more information on insect galls: http://edis.ifas.ufl.edu/pdffiles/IN/IN02200.pdf
Q: What is wrong with my oak tree?
A: Thank you for bringing samples of your oak tree into the plant clinic. These small structures on the stem are called bullet galls. These growths are caused by a very tiny female wasp, Disholcaspis quercusvirens, placing an egg into the stem. The plant actually forms tissue around the egg, which develops into the gall. The egg pupates inside the gall and when it is fully developed it cuts an exit hole into the gall. The bullet galls have a sugary exudate that attracts stinging insects and ants from late summer to fall. In the home landscape, these galls are of little economic value. However, if these galls are formed on trees grown in the nursery then they can become a huge economic reduction. Chemical pesticides are generally applied during December for moderate control. Light pruning to remove stems may also prove beneficial.
Q: What is this tree? The leaves are changing color now. I have only one of these on my property.
A: Thanks for bringing in a sample for me. Right now this tree, Turkey oak, Quercus laevis, is showing us rusty, brown colors. Quercus is the Latin name for “oak,” and laevis comes from the Latin word meaning “smooth, slippery, or polished,” which refers to the tree’s nearly hairless leaves. Turkey oak, or turkey-foot oak, received its common name from the shape of its leaves, which resemble a turkey’s foot. These trees can be found from Virginia, south to central Florida, and west to southeastern Louisiana. Turkey oak is also known as scrub oak—referring to the habitat where the species is commonly located. Turkey oaks provide food for wildlife such as the black bear, white-tailed deer, and wild turkey. This tree has a high resistance to wind and is also drought tolerant. Turkey oak trees grow to about 40 feet but can reach heights of 70 feet. They are often found growing in high bluff areas so here in Nassau County, Florida we can find them in Hilliard and Yulee. Turkey oaks have been known to produce large amounts of pollen in the spring which can cause problems for people with allergies. The tree’s wood has been used for lumber and general construction, but is commonly used for fuel wood, barbecuing, and farm construction. http://edis.ifas.ufl.edu/fr312
Q: What is the name of this moth? What does it eat?
A: I believe the moth is the adult form of the spiny oakworm, Anisota stigma. It is a very common moth and is found throughout the eastern part of the United States from lower parts of New England down to central Florida as far west as Texas and Minnesota. The adult causes no damage to our landscape plants but the caterpillar feeds on numerous tree leaves – most specifically oaks. The spiny oakworm larvae can be an aggressive feeder but generally it feeds late in the season when most of the leaves of the oaks will be defoliating anyway. Here in the south, the damage is minimal and mostly aesthetic. Fully grown larvae enter the soil, pupate, and overwinter in the pupal stage. Usually only one generation develops during a year so they are not considered important enough for chemical control. If there is significant loss of foliage, it is possible to reduce the overall growth of the tree, but a severe infestation would have to occur for us to be concerned. The photos I have attached are of the early oakworm moth stage with wing buds. The wing buds have not fully developed which may take several hours to complete. The adult spiny oakworm moth is also photographed. The robust body is bright orange with rusty-brown wings and a distinct white dot. The wings have an iridescent purple cast – very pretty. Females are larger than males.
Q: Enough already, what is with all the acorns falling? When will this ever stop? My front yard, sidewalk and driveway are so messy.
A: You are not the only one who has asked me this question recently. Everyone, but the squirrels, seems to be unhappy with the number of acorns falling from the oak trees this year. I can almost hear my mother’s voice responding to this question – “when they are good and ready” is exactly when the trees will stop dropping acorns! This is one of those things we have little control over but the general rule is oak trees take about 3 weeks to drop all their acorns – sometimes shorter and sometimes longer. The mess should be over soon – but wait for it, wait for it….next we will have oak leaves dropping! On the bright side, the leaves can be used as mulch for trees and shrubs. This type of mulch is free and adds wonderful nutrients to the soil. Just be sure to only have about 2-3 inches of mulch around shrubs and never let it touch the trunk of any tree or shrub. If you have a mulching lawn mower, this will help break up the leaves into smaller pieces which will enable them to decompose faster.
Q: I heard you talking about how the pollen from the oak tree flowers might be causing some of our allergy problems. I have never seen an oak tree flower. Am I missing something?
A: Oaks are monecious which means the tree has male and female flowers located separately on the plant, the flowers clusters are called catkins. The female flowers are classified as pistillate and the male flowers are labeled staminate – aren’t you glad you asked? I put that piece of trivia in this article just to remind the Master Gardener volunteers the importance of the Botany class lessons I taught. You would have to look very close to see the female flowers as they are quite small – which makes them extremely easy to miss. The male flowers on the other hand, are yellow-green, long and slender. They are not necessarily attractive either but right now they are everywhere, hanging from oak trees and putting off loads of yellow pollen all over our cars and outdoor furniture. It is the production of oak and other tree pollen which has caused many of us to have itchy, burning eyes and runny, red noses.
Q: I have hundreds of small balls under my oak tree. They are actually parts of oak leaves rolled up. I cannot find anything inside but I am concerned they are harmful. What are they?
A: I received several calls and a few office visits regarding large numbers of these objects being found under oak trees. These are the result of a small weevil called the Leaf-Rolling Weevil, Homoeolabus analis. These insects are commonly found in the Northeast part of the U.S., down to Florida and over to Texas. The Live Oak is the preferred tree leaf. The roll, called a nidus, is sometimes dropped to the ground and other times the nidus is left on the leaf. Female leaf-rollers lay one egg on the section to be cut and the egg develops into a larva while protected by the leaf layers. The adult weevil has a reddish-brown exoskeleton with black legs, head and snout. Adult Leaf-Rolling Weevils eat holes in oak tree leaves or skeleton the upper leaf tissue for food. Since the weevil causes little damage to the tree, we do not recommend applying any chemical control. For more complete information read the publication attached which is from UF/IFAS Department of Entomology and Nematology. http://edis.ifas.ufl.edu/in753
Q: What is causing this unusual growth on my oak tree?
A: Your oak tree is producing galls. This particular gall, called the leafy oak gall, is actually tree tissue forming around the egg of the wasp, Andricus quercusfoliatus. Oak trees are notorious for forming all types of galls as a result of insects (usually wasps or flies) ovipositing (egg-laying) into the tissue of the leaf, bud or twig of the tree. Galls generally cause no harm to the tree and provide an important role in protecting the predatory insect through adulthood. Some galls are very attractive and mimic fruit, cones or nuts. Galls are best left alone. If they are unsightly, some light pruning to remove the growth will give the best control.
Q: I have orange growths on limbs of my oak tree. Will it damage the rest of my oak?
A: Thanks for sending me photos of your oak tree; it helped me identify the problem right away. The orange growths on the limb of your oak are shelf fungi. The portion you see outside the tree is called the fruiting body of the fungi. The presence of the fruiting body on the outside indicates the limb is rotting from the inside out. Inside the limb can be found millions of thin white fibers called mycelium. Fungal mycelia have the ability to break down the wood fiber into material they can digest. The fungi may live off the tree for months or even years before the fruiting body appears on the outside. The presence of the fruiting body is a clue which reveals the limb may break off at any time. If the limb is hanging over a car or house or any other important structure consider removing it before it falls off and potentially causes damage. Certainly, this would not be the best place to put a picnic table either! Fungal shelves found on the trunks of trees or palms indicate the whole tree may be weakening and in danger of failing. There is no chemical application to cure this fungal growth; it is merely doing its job of breaking down dying matter. This is truly the full circle of life in action.
Q: I have this beautiful tree that produces red fruit every spring. The tree is very large and sometimes the fruit is in clusters. What can you tell me about this tree?
A: This tree puzzled me for a while because it had catkins like an oak or willow. Only the young leaves were present and they looked similar to willow leaves, but the fruit was very beautiful and unusual. After much searching and discussion with other people in the county, I decided to open up the seed of the fruit and I found a small, white insect larvae. This made me realize I had a gall on my hands. This gall is called the roly poly oak gall. It's caused by gall wasps in the genus Andricus and is called roly-poly because the wasp grub develops in that loose-egg-like structure inside the hollow gall. If the gall is shaken, the grub in its structure rolls around – hence the name “roly poly”. The biology of roly-poly galls is still not well known. Oaks can have numerous types of galls. Out of the over 800 species of gall making wasps in North America, 731 of them attack oaks. Oak deformities are of various sizes, shapes, and colors on leaves, twigs, flowers, acorns and buds. Galls are so commonly found on oaks that many people think the galls are typical parts of the plant. Some early botanical drawings actually show galls as part of the normal plant. The good news about galls is the majority does little or no damage to trees. The trees are just well accessorized. Generally there is enough unaffected foliage for the trees to remain vigorous and therefore this is one less thing you need to worry about.
Q: My oak leaves have these distortions all over the leaves. What causes this?
A: Oak leaf blister is a common leaf disease among oaks in Florida and is caused by fungus. Although infected trees may have unsightly leaves, serious damage is uncommon. The fungus which causes leaf blister attacks only the leaves, and does no damage to other parts of the tree. Spores of the pathogen infect young oak leaves. As the pathogen develops within the leaf, it causes a disruption of normal development of leaf cells. The infected tissues appear swollen or blister-like and lighter in color. Severe infections can cause the leaf to become curled or twisted. Over time the infected tissues die, leaving gray-brown areas scattered within the given leaf. Leaf blisters first appear on the underside of leaves as small, slightly depressed gray areas. Over time the infection causes the leaf to become deformed, forming a blister. The blisters can grow to be 1/3" or larger and can be seen on both sides of the leaf. There may be several blisters on a leaf and if blisters occur near the edge, leaf curl may result. Oak leaf blister is not usually noticed until many leaves have become very blistered or excessive leaf fall occurs. Any oak can be infected; however live oak, water oaks, and laurel oak are preferred hosts. Oak leaf blister was especially prevalent last season because of early spring rainy weather favorable for disease development. The fungus which causes the disease infects young leaves as they emerge, and the distinctive symptoms of oak leaf blister appear several weeks later.
Q: I have 2 beautiful huge oak trees. The problem is they are slowly being taken over by moss. Is there anything to kill the moss without calling a professional service? Also, how did the moss get started growing in the trees? They are very old trees and we have never had this problem before. Any advice you could offer would be greatly appreciated.
A: Spanish moss and ball moss are actually epiphytes, which mean they obtain their nutrition from the environment. They are not parasitic and cause no direct damage to trees. Heavy infestations on pecans can cause limb breakage, but otherwise the moss is of little consequence. In fact, a green colored Spanish moss is an indication of clean air. A copper sulfate solution can be sprayed on the moss to control it, but beware because the solution may be detrimental to new growth on trees or surrounding plants if the copper solution is drifted by the wind. Hand removal using a pole or rake is possible, but think safety first. The plant reproduces by seeds and vegetative growth. When small pieces of the plant are broken off and moved (usually by wind or animals) to another appropriate growth site, they will begin to grow into new plants. Spanish moss can be spread easily by violent storms, which we have been experiencing for the last few months. For more information on Spanish moss and ball moss check out the University of Florida website : http://okeechobee.ifas.ufl.edu/News%20columns/Whats%20In%20My%20Tree.htm
Q: Several oaks in my yard have died. I have noticed numerous growths on the limbs, which are supposedly galls. I want to know if they are killing my trees and if they will spread to the other trees. I have also lost two mimosa trees.
A: The galls are not causing the trees to die although they may look unsightly. It is of course sad to lose any tree but Mimosa trees are not long living trees and some are classified as invasive. After talking to you we finally discovered what I believe the true culprit of your oak death to be – mistletoe. People don’t realize this plant is a parasite. As you drive down A-1A you see many of the trees along the roadside contain mistletoe and I have seen many trees all around this county full of this parasite. Totally there are about 170 species of mistletoe. Seed dispersal is mainly done by birds. Even though the seed goes through the birds digestive system it retains sticky hair-like structures that enable it to remain attached to the tree. Once a seed germinates, it can penetrate the host plant by growing through the bark into the water conducting tissues. Symptoms of damage show up first in twig dieback above the point of the mistletoe attachment. It is interesting to note that the tree does not respond by compartmentalizing after the intrusion, which would normally occur if the tree was wounded or pruned. Mistletoe receives water and nutrients before the host tree so in times of drought, the mistletoe causes even greater stress to the host tree. It can live in the trees for many years but it is slowly usurping the strength out of the tree. All parts of the mistletoe contain toxic substances that inhibit protein synthesis in the intestines of humans, but the toxicity is rarely fatal. Mistletoe infections can be controlled by pruning infected branches. Branches must be cut one to two feet back of the visible infection area. Cutting only the top green portions of the plant can induce the development of many shoots in other parts of the tree so it is best to sacrifice tree limbs.
Q: What is this pink stuff growing on my oak trees? Will it kill the tree?
A: This growth is called lichen, which is a combination of algae and fungi. Lichen is not parasitic as some people believe but is an example of symbiosis. The fungi provide a home for the algae and the algae provides food. Lichen, along with the green Spanish moss, can often be indicators of healthy air. In this instance, they both tell us the air in your landscape is healthy and clean. Your tree may be in decline for other reasons but the lichen and the Spanish moss are not the cause.
Q: My neighbor’s oak died suddenly. Now mine is doing poorly and I wanted to be sure it wasn’t a disease that might spread to mine. What could have caused it?
A: Thanks for bringing me cuttings of your oaks; one was a Laurel Oak and the other a Sand Live Oak. It was important to us to be able to identify your oaks then determine what might be causing their decline. We were able to eliminate construction damage and poor pruning on your trees although that may have been what started the decline on your neighbor’s trees. Compacted soil around the roots is another stress factor for trees so we discussed adding pine straw under the tree canopy and adding water to be sure the roots are hydrated. After examining the twigs we discovered black twig borers, Xylosandrus compactus. This is one of the few ambrosia beetles that will infest healthy trees, in fact, 224 species of trees are susceptible to infestation. Most ornamental shrubs and trees do not die from the infestations but the twig borers can cause stem dieback which can be unsightly. With additional environmental stress such as drought, construction or compacted soil around the root area; the tree may eventually die. In north Florida, adults spend the winter in damaged twigs of host trees and emerge during late February. The females attack new twigs in March and brood production begins in April. Highest population levels occur from June to September. Best management practice is to remove any fallen twigs and/or prune damaged twigs to control this beetle. Regarding your trees, it was evident the Laurel Oak showed greater depth of decay from the beetle than the Sand Live Oak. I suspect you may see the decline of the Laurel Oak before the Live Oak as the Laurel is less able to compartmentalize the decay. Consider hiring certified arborist to come and do some corrective pruning if necessary. You can locate a list of certified arborist in this area by going to the Florida Chapter of the International Society of Arboriculture: http://www.isa-arbor.com/findArborist/verifyArbByLoc.aspx
Q: I cut this structure off a tree in south Florida. Can you tell me the name of the tree?
A: I am not familiar with many of the plants grown in south Florida so I asked the help of a few of the local Extension agents in this area. Ray Zerba, the Horticulture Extension agent in Clay County, used to work in south Florida and he immediately recognized the fruit immediately as belonging to the screw pine tree, Pandanus utilis. Screw-Pine is really not a pine tree at all but more closely related to palms and grasses. It is capable of reaching 60 feet in height but is not usually seen over 25 feet in USDA hardiness zone 10 and 11, with a spread of 15 feet. This means it should not be planted in your cold hardiness zone of 8b. Screw-pines are dioecious which means the male and female flowers are produced on separate plants (similar to hollies). The female plant is the one producing the large fruiting body in the photograph. Growth rate is slow to moderate, depending upon fertilization and watering schedules, and Screw-Pine is very popular for use as a specimen or grown in containers. It is important to remember to be careful about transporting seeds and plants from one part of the country to another. There always exists a possibility for these plants to become a pest or nuisance when transplanted. In addition, we have seen so many examples of insects and diseases being spread simply by humans moving plants from one site to another. When you are curious about a plant, consider taking a photograph of it, research it (or call your Extension agent), and then determine whether to plant it. But remember, sometimes diseases and insects are difficult to detect, therefore purchasing plants from a reputable nursery is always the preferred method of obtaining specimens for your landscape.
Q: What is causing my pine needles to turn brown?
A: Your pine trees, which are located across from the beach, are probably Japanese Black Pines, Pinus Thunbergiana. I found numerous, tiny pine needle aphids on the pine tree with the brown needles. The aphids are sucking out the plant juices from the needles and causing them to turn brown. You could use insecticidal soap or horticulture oil on the needles. These two products can be found at any garden center. Be sure to follow the directions on the label and apply it thoroughly to all the pine needles. Avoid applying it when on windy days, which is difficult to do with normal ocean breezes, so pick the calmest time of day. Applying these insecticides should not be too difficult since the trees are only about 10 feet tall with some of the limbs close to your height. The trunks on two of the trees showed signs of fungal damage, which means the trees will eventually decline, although we cannot say exactly when death will occur. There is no chemical spray that can be applied to correct the damage. The fungus is easily spread from tree to tree as the fungal spores are spread by wind. Removing the trees may be a viable option. The good news is the trees are in the middle of your landscape so they pose little danger to any structure or human if they fall.
Q: What is your opinion about keeping slash pines on residential property? Two other neighbors with bordering properties have had their pines removed and 2 tree companies recommended we remove ours too. The tree companies say these pines are fast growing and are for commercial use only.
A: I spoke to the Nassau County Forester, Steve Gaul, since he has more experience with pines. He said these pines are fine for homeowner landscape use and removal is not necessary. Slash pines, Pinus elliottii, can reach heights up to 100 feet with trunk diameters from 2-4 feet. This tree provides shelter and food for many forest critters and birds. It can tolerate a wide range of soil and light conditions. The best criteria for removing a tree is: it is at risk of falling, it is invasive, it has a fatal disease or infested with insects.
Q: Is this pine tree a long leaf pine?
A: Thank you so much for bringing in a clipping of your pine tree sapling. Since it is young, it makes it a little more difficult to identify because the needle length may not be at its mature growth level. But there is one other characteristic that makes the identification process a little simpler. When we identify pines one structure we examine is the part that holds the needles, which is called the fascicle. With the exception of one species, the long leaf pine fascicles hold 3 needles. Slash pine fascicles hold combinations of two or three. Your pine tree had two and three needles per fascicle and therefore it is probably a slash pine, Pinus elliottii. The female cones of slash pines usually stay on the tree until the second year, so these trees often are seen with cones while other pine trees have already dropped their cones. It is not uncommon to plant slash pines in reforestation areas as they grow quickly. However, they occur naturally in wet flatwoods and along coastal regions, which is where your property is located.
Q: I would like to plant some pines but I don’t want them to get too tall. Do you have any suggestions for smaller growing pines?
A: One choice would be the Pinus pinea, Italian Stone Pine or Umbrella Pine, which generally gets no taller than 35 feet. The Stone Pine forms an unusual round top. Trees grow well in slightly alkaline to acid soil. Umbrella Pine should be grown in full sun on well-drained soil. Needles are found in fascicles of 2. Italian Stone Pine develops large branches on the lower portion of the tree. This is normal and can be encouraged as long as none of them develop included bark. Something always seems to be falling from this pine tree; needles, sap, branches, and fruit appear on nearby cars, roofs and sidewalks year round so take that into consideration when choosing a planting site. It is important to maintain only central trunk leader to the top of the plant. Probably the most serious problem of Pines in areas with high pH irrigation water is pine chlorosis. Another possible choice of pine trees would be the Pinus glabra, Spruce Pine is commonly found between 30-50 feet tall. It becomes one of the nicest, soft-textured pines available for urban planting. Growing in full sun on moist fertile soils, this North American native will also tolerate poor, dry soils, as well as wet sites better than other Pines. Trees are very tolerant of urban conditions and have survived and grow well along streets. Trees grow in southeastern US into northern Florida on river banks and swamp edges. Soils are acid and typically sandy and periodically waterlogged. Like many trees and shrubs it grows best without grass competition. Spruce Pine is unusual among the Pines in that it will grow in partial shade. Needles found in fascicles in groups of two, similar to the Italian Stone Pine.
Q: My wife and I recently were visiting Nassau and wanted to know the name of the trees with orange flowers which appear to be growing all over the area.
A: Thanks for the photo, it helped tremendously. This doesn’t happen often but Nassau County, Florida (where I am located) is confused with Nassau, Bahamas or Nassau, New York. However, I am fairly certain I can help you as I recognize the tree as one which is grown in the South Florida. The tree you referred to is the Royal Poinsiana, Delonix regia. This tree commonly grows wider than tall reaching heights up to 40 feet with potential 60 feet spreads. It is a deciduous tree with brilliant red-orange blooms, literally covering the tree tops from May to July. There is nothing like a Royal Poinciana (or better yet, a group of them) in full bloom. The fine, soft, delicate leaflets provide dappled shade during the remainder of the growing season, making Royal Poinciana a favorite shade tree or freestanding specimens in large, open lawns. The long (sometimes up to 18 inches long), dark brown seed pods hang on the tree throughout the winter, then fall on the ground in spring creating a potential nuisance. Therefore this tree would not be the best choice for urban environments. It flowers best when located in full sun and tolerates a wide variety of soil conditions. You are located in Texas and I suspect your cold hardiness zone would not accommodate this tree, which grows in 10B – 11.
Q: What is causing the growths on my bay tree leaves?
A: The red bay psyllid, Trioza magnoliae, was originally called the bay magnolia psyllid (Ashmead 1881) because the host plant from which it was originally described was believed to be the plant that is now known as sweet bay (Magnolia virginiana L.) which is in the family Magnoliaceae. However, there are no known verifiable records of this insect on plant species other than native species of Persea bay trees (Mead 1967) in the family Lauraceae. Most, but not all, species of psyllids are narrowly host specific (Hodkinson 1984), and R. magnoliae is not known to use even other species of Lauraceae besides P. borbonia (redbay tree) and P. palustris (swamp bay) as hosts. Therefore, it is referred to as the red bay psyllid. Red bay psyllid galls are almost universally present on P. borbonia and P. palustris. In fact, they are so omnipresent that Nelson (1994) has suggested using the presence of the galls as an "identification clue" to these species of Persea. The galls cause absolutely no harm and no steps should be taken to cure the tree. Red bay psyllids are not believed to attack avocado, Persea americana Mill, which has also been threatened by the ambrosia beetle. Persea borbonia, redbay, as well as other southeastern U.S. Lauraceae and some of the organisms dependent on this tree are now threatened by a lethal fungal species living in the exotic red bay ambrosia beetle, Xyleborus glabratus Eichhoff. It is this beetle which has destroyed thousands of acres of our native red bay species. This information was provided through the Features Creatures article produced by the UF/IFAS Entomology & Nematology Department: http://entnemdept.ufl.edu/creatures/orn/trees/red_bay_psyllid.htm
For more information on the redbay tree check out the University of Florida publication by Dr. Ed Gilman: http://edis.ifas.ufl.edu/st436
Q: Did you know about the trees dying on Amelia Island? I am not sure but I think they are oaks. The leaves are totally brown all over the tree and they have not dropped off. Do you know what is causing this?
A: I have received dozens of calls and office visits about these trees. The news is not good regarding the cause and prognosis of these dying trees. The trees are not oaks but Redbay, Persea borbonia. We actually have an invasive beetle attacking the trees. The redbay ambrosia beetle, Xyleborus glabratus Eichoff, was first detected around 2002. Since then we have noticed trees dying from North Carolina down the coast of Florida. The beetle introduces fungi which block the vascular system of the bays and they die an untimely death. Most ambrosia beetles choose trees and shrubs already dying but there are a few exceptions. The X. glabratus is one of those exceptions as it attacks perfectly healthy trees. We do know the beetle is attracted to other tree species but oaks are not on the list at this time. The trees need to be cut down and removed. We have no chemical control or management at this time although extensive research is being currently conducted. Several local tree companies have certified arborists on staff and they know the correct protocol. When contacting a company for tree removal it is important to ask if they have a certified arborist on staff. Equally important is proper insurance coverage for liability and worker’s compensation. Tree companies pay a great deal of money and dedicate numerous hours to ensure their workers are properly insured and educated. They are more than happy to share that information with you.
Q I just moved here and I discovered this small little tree in my backyard. Do you know what it is?
A: Well, welcome to Nassau County, Florida. I am glad you brought me a twig with the leaves which helped me identify it quickly. It is called a red buckeye, Aesculus pavia. Red Buckeye is a small North American native tree capable of reaching 25 to 30 feet tall in the wild though is most often at 15 to 20 feet high. Red Buckeye is most popular for its springtime display of three to six-inch-long, upright, red flowers which are quite attractive to hummingbirds. These blooms are followed by flat, round capsules which contain bitter and poisonous seeds. The large, dark green, palmate leaves usually offer no great color change in fall and often drop as early as late September. Red buckeye lives best in cold hardiness zone 6-9a and in full to partial shade. Attached is a publication from the University of Florida on the Red Buckeye. http://edis.ifas.ufl.edu/st064
Q: In your butterfly class you taught the sassafras tree was a good larval food source for some of the swallowtail butterflies. Can you tell me more about the tree?
A: The Sassafras tree, Sassafras albidum: is a native tree to North America – anywhere from cold hardiness zones 5a – 9a. It is deciduous, dropping its leaves when the cold weather appears. It can grow to heights of 60 feet with a 25 – 40 foot spread. Therefore, it would need plenty of space. Historically, the bark and fragrant roots were used for medicinal purposes. According to a publication from Pennsylvania State University, Sassafras was used by Native Americans as a cure-all for a broad range of ailments. An oil extract from the root bark was used to treat diarrhea, nosebleeds, even heart troubles. European settlers and their colonial sponsors were so impressed by the healing powers of sassafras oils the sassafras roots were exported back to Europe in great quantities. In 1602, one ton of these roots sold for 336 pounds Sterling (about $25,000 in modern currency). Leaves were brewed into a medicinal tea and extracted oils were used to make perfume, candy, soap, and root beer. The University of Florida believes we should be planting sassafras for the outstanding display of fall leaf colors. The multi-lobed leaves have a distinctive aroma when crushed. Sassafras prefers well-drained, acidic soils and can be grown in most any type of light (full sun to partial shade). It is highly drought tolerant once it is established. Its ability to tolerate salt is unknown. In spring, before the leaves appear, the tree produces yellow, lightly fragrant flowers followed by dark, blue colored fruits which ripen in the fall. These fruit provide an excellent source of food for birds and other wildlife. Although the male plants have showier blossoms, it is the female plants which produce the fruit. Both sexes must be planted to insure good fruit production. Sassafras frequently develops a multiple trunk due to sprouting at the base. Sprouts appear to originate from the root system forming a cluster of showy, grey fissured trunks growing from the soil. This characteristic has helped it invade and colonize old fields and other disturbed sites. Prune early in the life of the tree to form a single trunk suitable for urban landscape planting, or grow with multiple trunks for a dramatic specimen. Single-trunked trees are best-suited for street tree planting and other urban and suburban areas, and they usually maintain this good form without pruning.
Q: We bought 2 spiral junipers and transplanted them to new pots. The lady we bought them from said it was okay to trim the roots periodically to keep them from getting too big. So....My husband trimmed the roots to fit them in the new pots. The pots we put them in kept tipping over so we had to transplant them again. Now, they're dying. They continue to get browner every day. We have fertilized them and think that they may have gotten too much water. What can we do to save them?
A: The junipers of course were lovely specimens and I can see why you would be concerned about their progress. Root pruning is a very delicate procedure and usually on these kinds of specialty trees it is better left to an expert. The delicate small roots are the most essential for water and mineral absorption and removing them places the tree or shrub under dire stress. It would have been better to put the trees in slightly larger pots to accommodate the essential roots, and then you could have pruned some of the larger roots but left the fine, absorption roots alone. Root pruning is often done on trees and shrubs 10-12 weeks prior to transplanting into larger ground plots then the plant is watered to encourage the growth of the more roots at the pruning site. Root pruning is also done on important bonsai plants and specimen trees such as yours which are found in museums or commercial locations. However, even on these expensive trees and shrubs large portions of the roots are seldom removed at any one time. One other note, adding fertilizer to a new transplant often adds more stress to the now tender and vulnerable roots. Water would have been all the plant needed at the initial transplanting. It may recover, but do not be overly optimistic. I am afraid we may have to chalk this one up to experience. Continue to water the trees, but be sure they are well-drained and do not add any fertilizer.
Q: I have this beautiful tree growing wild on the side of my yard. Can you tell me what it is?
A: It helped to have a clipping of a stem and leaves of this plant plus to know it grew up as a volunteer in your landscape. At first glance I thought it might have compound leaves, which would have made it easier to identify because only a few trees have compound leaves. However, after searching my native tree books I was able to discover this tree is probably a Sugarberry or Sugar hackberry, Celtis laevigata. The leaves of the hackberry tree are simple and the leaf base is oblique or uneven, which narrowed the identification field. Sugarberry is a very large, broad, fast growing deciduous North American native tree found in most states of the U.S. except around the Great Lakes region. This light green leaves turn bright yellow in fall and can be showy in some years. The gray-brown to silvery bark has some warty projections or corky ridges, making it attractive in wintertime. The Sugarberry has a tendency toward trunk rot especially if weed-eater or mower damage occurs. This susceptibility to trunk rot in mature trees is similar to that of a Laurel Oak. Remember it is best to keep lawn grass away from the trunk and roots of trees and shrubs to avoid mechanical damage to the roots and trunk. Sugarberry will grow in a variety of soil types but grows best in moist, fertile soils in a full sun location, though it will tolerate partial shade. It is sensitive to highly alkaline soils and leaves will show premature yellowing if the soil pH is too high. Sugarberry is moderately drought and salt-tolerant once it is established and is very adaptable, growing in wet sites fairly well.The tiny, berry-like, sweet fruits attract many birds. Sugarberry should be included in any natural landscape setting and is an under utilized tree. This information was adapted from UF/IFAS publication by Dr. Ed Gilman & the US Forestry Service: http://hort.ufl.edu/trees/CELLAEA.pdf
Q: What is wrong with my sweet gum tree?
A: It was easy to identify the “problem” since you brought a specimen into the office. Your sweet gum tree, Liquidambar styraciflua, commonly has these corky growths along the stem and trunk area. This is not a disease or an indication of weakness on the tree. So, enjoy the tree and don’t worry about it. Plant sweetgum trees 10 feet or more from sidewalk or driveways it has large, aggressive roots may lift curbs and sidewalks. The fruit may be a litter nuisance to some in the fall, but this is usually only noticeable on hard surfaces, such as roads, patios, and sidewalks, where people could slip and fall on the fruit. The cultivar ‘Rotundiloba’ is fruitless so it may be a better choice in urban settings.
Q: What is causing my sycamore leaves to crinkle and curl?
A: Thank you for bringing in some samples of your tree damage. It would have been difficult to locate the small, white cocoons and then identify the insect without seeing those samples. The caterpillar is probably from the Sycamore moth, Halysidota harrisii. The adult moth has a hairy, yellow body, with solid white underwings and black and white markings on the larger upper wings. The caterpillar has chewing mouth parts and they chew on the leaves of sycamore, hickory, poplar and maple. They usually cause very little damage unless their populations become large, which has occurred this year. When the caterpillar numbers are substantial, then they have been known to feed on other prized ornamentals such as Japanese maple, rose, apple, and live oak. Photo was taken by Henning von Schmeling from Mississippi State University.
Q: Would Tea Olive be a good hedge choice here?
A: Tea Olive, Osmanthus fragrans, is a small evergreen tree or shrub which can grow up to 25 feet tall but typically is about 15 feet tall with10 feet spread. The lustrous, medium‐green leaves have paler undersides and are joined from October through March by a multitude of small, but extremely fragrant, white blossoms. They perfume a large area of the landscape and can be showy in some years. I believe they would make an excellent hedge as long as you kept them tall. It tolerates full sun to part shade but does poorly in wet sites and where soil does not drain well. It is not salt tolerant and although can fit into a landscape well with typical lawn irrigation, the one at my office receives no additional water outside rainfall and does beautifully. No pests or diseases are of major concern. Scales and nematodes may present a problem, and mushroom root rot is troublesome when the soil is kept too wet. With its upright oval to columnar growth habit in youth, Sweet Osmanthus is ideal for use as an unclipped hedge or trained as a small tree, and should be placed where its fragrance can be enjoyed. Since the flowers are not particularly showy, people will wonder from where the delightful fragrance originates. This is a subtle plant which should be used more often in Southern landscapes. Plants thin somewhat in the partial shade, but form a dense crown in a sunny location. Planted on 4 to 6 foot centers, Sweet Osmanthus can form a wall of fragrance during the fall, winter and spring and should be planted more often. They will not grow as fast as Leyland Cypress, but think of this Osmanthus as a substitute for use in a sunny spot. Plants can be clipped to form a denser canopy, but flowers form on old stems.
Q: I saw one of the trees in the back of the demonstration garden with white flowers. The flowers hang down like bells. What can you tell me about it?
A: The Two-winged Silverbell, Halesia diptera, is one of the newest additions to the Urban Tree portion of the UF/IFAS Nassau County Demonstration Garden. We have it in a slightly shaded area just in front of a wooded section. This tree prefers shade but can be grown in full sun; similar to the same type of environment where we often plant dogwood trees. Two-winged Silverbell trees are found throughout much of the United States in cold hardiness zones 5 through 8b. Its normal growth height will be between 20 – 30 feet with an equal spread. The white, bell shaped flowers appear in the spring. It likes moist, well-drained soils so it is important to keep the area under the canopy mulched to retain moisture. Two-winged Silverbell trees have no major pest or disease problems making this tree a perfect addition to most landscapes. Another benefit of the Two-winged Silverbell is the production of showy, small, yellow, fruit which attract birds. Some light pruning will be required to keep branches structurally sound. http://edis.ifas.ufl.edu/st290
Q: What is the name of the willow-like plant growing along the roadsides now? It is putting out thousands of puffy seeds.
A: I believe the plant you are referring to is the Carolina Willow, Salix caroliniana. It is also called Coastal plain Willow. This plant is found in 23 southern states and throughout most of Florida. You can see by the number of seeds it produces why it is so successful. Carolina Willow is considered a native to the Southeastern part of the US in wetland areas or along stream banks. It can grow to heights of 20 feet or more. It can tolerate a wide range of soil and water conditions. Carolina Willow Is a deciduous tree which means it drops its leaves during fall and winter.
Q: I have a tree in my backyard which I would love to have identified. In the fall the tree has clusters that look like tiny purple grapes. In the late spring the branches have, what looks like pompoms on it.
A: After so many e-mails and photo exchanges I am glad we were finally able to identify this tree for you. It is a Winged Sumac, Rhus copallina, which is a great tree for an informal landscape. The fruit and flowers of this tree attract wildlife. The Winged Sumac is found throughout most of the United States, can be grown in a variety of light and soil conditions, and is highly drought tolerant.
Q: I am new to the area and wanted to know if a yellow poplar will survive and do well in this area?
A: Welcome to Nassau County and to Florida. I would encourage you to try the yellow poplar, Liriodendron tulipfera, which has beautiful fragrant, yellow flowers and unusually squared tipped leaves. Tuliptree grows 80 to 100 feet tall and maintains a fairly narrow oval crown, even as it grows older. Tuliptree has a moderate to rapid (on good sites) growth rate at first but slows down with age like most of us. The soft wood reportedly is subject to storm damage but the trees held up remarkably well in the south during hurricane ‘Hugo’. It is probably stronger than given credit. The largest trees in the east are found in the Joyce Kilmer Forest in NC. Some of these North Carolina trees reach heights of more than 150 feet with seven-foot diameter trunks. The fall color is gold to yellow being more pronounced in the northern part of its range. The scented, tulip-like, greenish-yellow flowers appear in mid-spring but are not as ornamental as those of other flowering trees because they are far from view. The best time to plant it is spring but those in containers can be planted almost year round. During hot, dry weather interior leaves turn yellow and fall off. This condition is due to the weather and is not a disease. The problem is most common on newly transplanted trees, but also develops frequently on established trees. Yellowing may be preceded by small, angular, brown spots on the leaves. Tuliptrees should be planted in full sun. They can tolerate occasional wet soil and will grow in most any type of soil pH.