Southern Red Cedar
Juniperus silicicola


    INTRODUCTION

    This densely-foliated, wide pyramidal, columnar or oval evergreen grows fairly quickly, ultimately reaching heights up to 40 feet with a 25-foot spread. . Some individual plants grow wider than tall as they grow older. Some botanists do not make a distinction between Juniperus silicicola and Juniperus virginiana. Its fine-textured, medium green leaves and drooping branchlets help to soften the rather symmetrical, oval juvenile form. Mature specimens of Southern Redcedar take on a flat-topped, almost windswept appearance, making them very picturesque. Bark and trunk on older specimens take on a delightful, 'old-tree' look.

    GENERAL INFORMATION

    Scientific name: Juniperus silicicola
    Pronunciation: joo-NIP-er-us sill-liss-sih-KOLE-uh
    Common name(s): Southern Redcedar
    Family: Cupressaceae
    USDA hardiness zones: 8 through 10
    Origin: native to North America
    Uses: Bonsai; wide tree lawns (>6 feet wide); medium-sized tree lawns (4-6 feet wide); recommended for buffer strips around parking lots or for median strip plantings in the highway; reclamation plant; screen; residential street tree; Christmas tree; tree has been successfully grown in urban areas where air pollution, poor drainage, compacted soil, and/or drought are common.
    Availability: generally available in many areas within its hardiness range

    DESCRIPTION

    Height: 30 to 45 feet
    Spread: 20 to 30 feet
    Crown uniformity: symmetrical canopy with a regular (or smooth) outline, and individuals have more or less identical crown forms
    Crown shape: columnar; oval; pyramidal
    Crown density: open
    Growth rate: fast
    Texture: fine

    Foliage

    Leaf arrangement: opposite/subopposite; whorled
    Leaf type: simple
    Leaf margin: entire; terminal spine
    Leaf shape: awl-like; scale-like
    Leaf venation: none, or difficult to see
    Leaf type and persistence: evergreen
    Leaf blade length: less than 2 inches
    Leaf color: green
    Fall color: no fall color change
    Fall characteristic: not showy

    Flower

    Flower characteristics: inconspicuous and not showy

    Fruit

    Fruit shape: round
    Fruit length: < .5 inch
    Fruit covering: fleshy
    Fruit color: blue; purple
    Fruit characteristics: attracts birds; no significant litter problem; showy

    Trunk and Branches

    Trunk/bark/branches: droop as the tree grows, and will require pruning for vehicular or pedestrian clearance beneath the canopy; showy trunk; should be grown with a single leader; no thorns
    Pruning requirement: needs little pruning to develop a strong structure
    Breakage: susceptible to breakage either at the crotch due to poor collar formation, or the wood itself is weak and tends to break
    Current year twig color: brown; green
    Current year twig thickness: thin
    Light requirement: tree grows in part shade/part sun; tree grows in full sun
    Soil tolerances: clay; loam; sand; acidic; alkaline; well-drained
    Drought tolerance: high
    Aerosol salt tolerance: high
    Soil salt tolerance: good

    Other

    Roots: surface roots are usually not a problem
    Winter interest: no special winter interest
    Outstanding tree: not particularly outstanding
    Invasive potential: little, if any, potential at this time
    Verticillium wilt susceptibility: not known to be
    susceptible
    Pest resistance: no pests are normally seen on the
    tree

    USE AND MANAGEMENT

    The dense growth and attractive foliage make Southern Redcedar a favorite for windbreaks, screens, and wildlife-cover for large-scale landscapes. Its high salt-tolerance makes it ideal for seaside locations. Redcedar can make a nice Christmas tree, and the fragrant wood is popular for repelling insects. Cedar Key, Florida, once had extensive redcedar forests before the lumber was extensively harvested and the wood used for chests and pencils. Although not currently used often as a street tree, its wood is strong, the foliage is clean, and the fruit is small making it a suitable candidate. There are some nice examples of street tree use in southern cities. With proper pruning to remove lower branches, it should adapt well to street-scapes.
    Planted in full sun or partial shade, Southern Redcedar will easily grow on a variety of soils, including clay. Growth may be poor in landscapes which are over-irrigated. Plants are difficult to transplant due to a coarse root system, except when quite small. Water until well-established and then forget about the tree. It performs admirably with no care, even on alkaline soil and along the coast. Usually insects and diseases are not a problem if grown in the full sun. There may be local restrictions on planting this tree near apple orchards because it is the alternate host for cedar-apple rust. Propagation is by seed, which germinate faster if planted as soon as the cones mature or if given a stratification period. Also, tip cuttings can be rooted. No cultivars are listed but there is ample opportunity to propagate and culture from the wide diversity of shapes and growth habits exhibited by this tree.

    Pests

    Usually none are serious.
    Bagworm caterpillars web foliage and debris together to make bags up to two inches long. The insects live in the bags and emerge to feed on the foliage. Use sprays of Bacillus thuringiensis. The insects can also be picked off the plants by hand. Juniper scale causes yellowed needles, and infected branches fail to produce new growth.
    The Juniper webworm webs twigs and needles
    together, causing them to brown and die. The larva is 1/2-inch-long and is brown with darker stripes. The larvae are often in the densest part of the plant and can go unnoticed.
    Mites cause stippled and bronzed foliage.
    Juniper scale is round and at first white, later turning gray or black.


    Diseases

    Twig blights cause death and browning of twigs tips. The diseases may progress down the stem killing the whole branch. Small lesions may be seen at the base of dead tissue. Prune out dead branch tips. Dieback from Kabatina blight appears in early spring, from Phomopsis in summer.
    Three rust diseases seen most often are cedar-apple rust, hawthorn rust, and quince rust. The most common is cedar-apple rust. On Juniper the disease forms galls and orange jelly-like horns in spring. The horns are most likely to form following periods of rainy, warm weather. Spores formed in the horns infect the alternate host. The diseases are more serious on the alternate host than Juniper. A separation of a few hundred yards may help avoid the disease. Prune out the spore horns when seen in the spring.
    Junipers are not tolerant of ice coatings. Expect dieback when Junipers are covered with ice for several days. Removing the ice is impractical.


    by Edward F. Gilman, professor, Environmental Horticulture Department, and Dennis G. Watson, associate professor, Agricultural Engineering Department, Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida, Gainesville FL 32611.

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Southern Red Cedar
Photo by Libby Wilkes

Rebecca Jordi
Horticulture Agent IV
County Extension Director
Contributing Editor
email: rljordi@ufl.edu