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Scientific: Two species, Fortunella margarita and Fortunella japonica, respectively
Common: nagami kumquat and marumi kumquat, respectively
Family: Rutaceae
Origin: Malaysian peninsula

Pronounciation: For-to-NEL-la SPEE-shes

Hardiness zones
Sunset
12-24
USDA 9-11

Landscape Use: Nice small patio tree, container tree, raised planters, great for small residential landscapes.

Form & Character: Upright and rounded, diminuative, non-offensive, formal, tropical, clean.

Growth Habit: Evergreen, woody, broadleaf perennial small tree, moderately grows from 6- to 25-feet tall with equalk spread, dense upper canopy.

Foliage/Texture: Oval to lanceolate medium-green leaves without a winged petioles, which distinguishes it from other local citrus; medium texture.

Flowers & Fruits: Small axillary, star-shaped, white flowers, 5 petals, magenta pink sepals, fragrant; fruits orange small to 1-inch long with sweet rind and acid juice vesicles. Fortunella margarita has oblong fruit, Fortunella japonica has rounded fruit. Regular fruit production in warm to hot summer locations.

Seasonal Color: Orange fruits in late fall through early spring sometimes overlapping with white flowers produced in early spring (later February in Phoenix).

Temperature: Heat tolerant to 115oF, cold hardy to 25oF.

Light: Full sun, but avoid reflected western sun on exposed trunk. Like other citrus, trunks of kumquat are often painted white to prevent sunscald injury, especially if trunks are exposed to direct sunlight by raising of the canopy base by pruning.

Soil: Like Citrus, needs supplemental micronutrient fertilizer in alkaline soils. Fertilzer applications should occur three times per year in January, May and September.

Watering: Regular water to maintain a densely-foliated canopy during the warm season. Taper off water applications during fall and ramp up water applications during spring. During winter, supplemental water in some years (with adaequate winter rainfall) will not be needed.

Pruning: A conservative approach to pruning kumquat is advised. Lightly head back or elevate canopy base only as needed. Avoid raising the canopy base. If in doubt about whether or not to prune, then its best to leave kumquat trees alone.

Propagation: Mostly grafted onto rootstocks of rough lemon and trifoliate orange.

Disease and Pests: Aphids and thrips, sometimes scale, phytophthora root rot.

Additional comments: Kumquat is a good mesic small landscape tree for smaller spaces. Fruit rind used for jellies, etc. Nice container plant when grafted onto dwarfing rootstock. Special care is needed to maintain proper nutritional status of kumquat. Fertilizer in January, May, and September with 0.7 pounds of nitrogen per tree. Kumquats might need Epsom (magnesium sulfate) salts once per year and chelated micronutrient fertilizers (liquid formulation best for landscape trees) twice per year.

The Fukushu or Changshou kumquat (Fortunella obovata) is a dwarf, compact, thornless tree from Japan with larger leaves and fruits that are about 1.5-inches long, oval, and depressed at the apex. The fruit rind is thin and orange when ripe. Its authority is disputed and some consider it to be a chance hybrid between two Fortunella species.

Special Note: X Citrofortunella sp. (limequat) is a bigeneric hybrid that includes three named varieties, Eustis, Lakeland, and Tavares. Variety Eustis and Lakeland are sister hybrids of the West Indian lime and the round kumquat (Fortunella japonica), and Tavares is a similar hybrid with the oval kumquat (Fortunella margarita). They were made by W. T. Swingle of the U.S. Department of Agriculture in Florida in 1909 and were named and described in 1913.

Resource: The Citrus Industry Vol. 1 (1967)