Culture
Best grown in evenly moist, loamy, slightly acidic, well-draining soils in full sun. Does not tolerate heavy, saturated soils. Hardy in Zones 9-11. In colder climates, keep containerized plants outdoors in summer and move indoors to a sunny location before the first frost. The flowers self-pollinate readily.
Noteworthy Characteristics
Citrus japonica, commonly known as kumquat, is a small, evergreen tree native to southern and eastern Asia. The first record of this plant is in Chinese literature from the 12th century C.E. Thin, dense branches bear dark green, glossy, elliptic foliage (up to 2" long and 1" wide). The branches, especially new growth, may also have thorns. In late spring, fragrant white flowers bloom singly or in clusters from the leaf axils. The orange fruits are round to oval in shape and small (less than 1" in diameter). There are many varieties in cultivation that produce larger fruits. Individual plants can reach up to 15' tall and 12' wide.
The genus name Citrus is from classical Latin.
The specific epithet japonica means "of Japan" and refers to the native range of this species.
The common name kumquat is comes from the Cantonese words "quat" meaning orange and "kam" meaning gold.
'Centennial Variegated' is a compact kumquat selection that features white and green variegated foliage as well as variegated fruit. The fruits (around 1.5" in diameter) have a smooth, thin rind with green and yellow streaks when immature and orange to red streaks once ripe. They have a strong citrus aroma with a sweet and tart taste. This variety is also essentially thornless.
Problems
No major pests or diseases of note. Spider mites, whiteflies, scale, and other common houseplant pests can be problematic if grown indoors.
Uses
Kumquat fruits are used to make jellies and preserves, and the entire fruit can be eaten raw. Takes well to container culture. Also suitable as a small ornamental tree in the home landscape, Mediterranean garden, or edible garden.