Meiwa Kumquat
Fortunella crassifolia

Kumquats are slow-growing, evergreen shrubs or small trees, from 2.5–4.5 metres tall, with dense branches, sometimes bearing small thorns. The leaves are dark glossy green, and the flowers pure white, similar to other citrus flowers, borne singly or clustered in the leaf-axils.

Kumquats originated in China (they are noted in literature dating to the 12th century), and have long been cultivated there and in Japan. They were introduced to Europe in 1846 by Robert Fortune, collector for the London Horticultural Society, and shortly thereafter into North America. Originally placed in the genus Citrus, they were transferred to the genus Fortunella in 1915, though subsequent work (Burkill 1931, Mabberley 1998) favours their return to inclusion in Citrus.

Four or five species are currently accepted:

  • Citrus crassifolia (syn. Fortunella crassifolia) - Meiwa Kumquat
  • Citrus hindsii (syn. Fortunella hindsii) - Hong Kong Kumquat
  • Citrus japonica (syn. Fortunella japonica, C. margarita, F. margarita) - Marumi or Nagami Kumquat
  • Citrus obovata (syn. Fortunella obovata) - Jiangsu or Fukushu Kumquat
  • Citrus polyandra (syn. Fortunella polyandra) - Malayan Kumquat

Kumquats readily hybridise with other members of the genus Citrus and with the closely related Poncirus. These hybrids are known as Citrofortunella; examples include the limequat, orangequat, and calamondin.

In appearance the kumquat fruit (generally called simply "kumquat") resembles a miniature oval orange, 3–5 centimetres long and 2–4 centimetres wide. Depending on variety, peel color ranges from yellow to red. A Nagami kumquat has an oval shape, while a Marumi kumquat is round.

Kumquat fruit is generally in season from late autumn to mid-winter, and can be found in most food markets with other produce.

Cultivation and uses

Kumquats are cultivated in China, Taiwan, Southeast Asia, Japan, Europe (notably Corfu, Greece), and the southern United States (notably Florida).

Climate

They are much hardier than other citrus plants such as oranges. The 'Nagami' kumquat requires a hot summer, ranging from 25 °C (77 °F) to 38 °C (100.4 °F), but can withstand frost down to about −10 °C (14 °F) without injury. It grows in the tea regions of China where the climate is too cold for other citrus fruits, even the Mikan (also known as the Satsuma) orange. The trees differ also from other Citrus species in that they enter into a period of winter dormancy so profound that they will remain through several weeks of subsequent warm weather without putting out new shoots or blossoms. Despite their ability to survive low temperatures, as in the vicinity of San Francisco, California, the kumquat trees grow better and produce larger and sweeter fruits in warmer regions.

Propagation

Kumquats are rarely grown from seed as they do not do well on their own roots. In China and Japan they are grafted onto the trifoliate orange (Poncirus trifoliata). This has been found the best rootstock for kumquats in northern Florida and California and for dwarfing for pot culture. For this reason they are often known as "Dwarf Fruit". Sour orange and grapefruit are suitable rootstocks for southern Florida. Rough lemon is unsatisfactory in moist soils and tends to be too vigorous for the slow-growing kumquats.

Uses

Kumquats are frequently eaten raw. As the rind is sweet and the juicy center is sour, the raw fruit is usually consumed either whole, to savour the contrast, or only the rind is eaten. The fruit is considered ripe when it reaches a yellowish-orange stage, and has just shed the last tint of green. The Hong Kong Kumquat has a rather sweet rind compared to the rinds of other citrus fruits.

Culinary uses include: candying and kumquat preserves, marmalade, and jelly. Kumquats appear more commonly in the modern market as a martini garnish, replacing the classic olive. They can also be sliced and added to salads. A liqueur can also be made by macerating kumquats in vodka or other clear spirit.

The Cantonese often preserve kumquats in salt. A batch of the fruit is buried in dry salt inside a glass jar. Over time, all the juice from the fruit is extracted through dehydration into the salt. The fruits in the jar become shrunken, wrinkled, and dark brown in color, and the salt combines with the juice to become a dark brown brine. A few salted kumquats with a few teaspoons of the brine/juice may be mixed with hot water to make a remedy for sore throats. A jar of such preserved kumquats can last several years.

In Taiwan, kumquats are a popular addition to both hot and iced tea.

In Vietnam, kumquat bonsai trees are used as a decoration for the Tết (New Year) holiday.

Selected from Wickipedia

Growing Tips

January

  1. Water as needed – especially 24-48 hours before a freeze
  2. Protect fruit grafted area if freeze will occur

February

  1. Water as needed
  2. Prune any water sprouts, suckers, rubbing or crossing branches
  3. Weed as needed

March

  1. Remove graft freeze protection if threat of freeze is over
  2. Fertilize program begins for lemon, orange, kumquat using citrus fertilizer.  Follow fertilizer label for frequency (slow release is used less often)
  3. Fertilize Tea Olive using acid loving fertilizer
  4. Fertilize loquat 2-3 times per year with Citrus fertilizer
  5.  Check for citrus insects and diseases, apply fungicide just at new leaf flush or after bloom drop

April

  1. Depending on citrus fertilizer label, apply fertilizer every six weeks or as directed.
  2.  Check for citrus insects; apply horticulture oil if insects are detected.
  3.  Check for diseases; apply fungicide just at new leaf flush or after bloom drop
  4.  Maintain 2-3’ unmulched area around citrus trees

May

  1. Depending on citrus fertilizer label, apply fertilizer every six weeks or as directed.

  2. Check for citrus insects; apply horticulture oil if insects are detected.

  3. Check for citrus diseases, apply appropriate fungicide
  4. Weed as needed

June

  1. Depending on citrus fertilizer label, apply fertilizer every six weeks or as directed.
  2. Check for citrus insects and diseases
  3.  Weed as needed

July

  1. Repeat May procedures
  2. Water, as needed

August

  1. Repeat May procedures
  2. Water, as needed

September

  1. Repeat May procedures
  2. Water, as needed
  3. Last month to fertilize citrus

October

  1. Check for citrus insects; apply horticulture oil if insects are detected.
  2. Check for citrus diseases, take appropriate action
  3.  Weed as needed

November

  1. Weed as needed
  2.  Protect grafted area if freeze occurs

December

  1. Weed as needed
  2.  Protect grafted area if freeze occurs

 

Pest Management Issues

Mites:  Citrus rust, Citrus red (purple mites) and Texas citrus. 

Scale:  Citrus snow, Purple scale. glover scale, red scale, yellow scale, Cottony cushion scale,  and Mealybugs.  These insects will be prevalent in spring and early summer.  Whitefly and Aphids can be found year round. 

Caterpillars:  Orange dogface is a large brown-and-white caterpillar is the larva of a black-and-yellow, swallowtailed butterfly. These butterfly caterpillars are left alone.  Grasshoppers and katydids feed in the summer; hand removal works best.  

Diseases:
Melanose, scab, greasy spot, Foot rot, HLB (Citrus greening), Canker are the most common problems.  Fungicide treatment must occur on a regular basis.  Light pruning, pruning of dead limbs and frequent removal of leaf and limb debris should occur on a regular basis.    

 

 

Meiwa Kumquat

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