Scientific: Two species, Fortunella margarita and F. 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: Small evergreen tree, rounded, formal, and clean.

Growth Habit: Moderate to 6 to 25 feet, 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, frangrant; orange fruit small to 1 inch with sweet rind and acid juice vesicles. F. margarita has oblong fruit, F. 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: 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.

Soil: Needs supplemental micronutrient fertilizer in alkaline soils

Watering: Regular water to maintain densely-foliated canopy.

Pruning: A conservative approach to pruning kumquat is advised. Lightly head back or elevate canopy base only as needed.

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

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

Additional comments: Fruit rind used for jellies, etc. Nice container plant when grafted onto dwarfing rootstock. Good landscape tree for small areas. 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.

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)