Atalantia hindsii (Champ. ex Benth.) Oliv.
Citrus × nobilis var. microcarpa Hassk.
Citrus hindsii (Champ. ex Benth.) Govaerts
Citrus inermis Roxb.
Citrus madurensis Lour.
Citrus margarita Lour.
Fortunella bawangica C.C.Huang
Fortunella crassifolia Swingle
Fortunella hindsii (Champ. ex Benth.) Swingle
Fortunella japonica (Thunb.) Swingle
Fortunella margarita (Lour.) Swingle
Fortunella venosa (Champ. ex Benth.) C.C.Huang
Sclerostylis hindsii Champ. ex Benth.
Sclerostylis venosa Champ. ex Benth.
Common Name: Round Kumquat
Citrus japonica is a much-branched, spiny, evergreen shrub or a small tree that can grow up to 5 metres tall with a trunk up to 20cm in diameter[
The plant is often cultivated, especially in China, for its edible fruit and also has a range of medicinal applications. It is sometimes grown as an ornamental[
E. Asia - China, Japan.
Evergreen broad-leaved forests; 600 - 1,000 metres[
|Other Uses Rating||
|Cultivation Status||Cultivated, Ornamental, Wild
Citrus japonica is native to the subtropical climate of southeastern China. It is not a very cold-hardy plant, when dormant it can tolerate short periods where temperatures fall to around -5[
]. The new growth is much more susceptible to cold and can be badly damaged at around 0°c[
]. Kumquats are hardier than the various other cultivated Citrus species (such as the oranges and the lemons) since they cease growth when temperatures drop below 13°c. For best results, however, it is best to grow them in a climate with warm to hot summers and winter temperatures that do not fall lower than between 4 - 10°c[
]. This is because the fruit is sweeter when it ripens in warm conditions[
Prefers a moderately heavy loam with a generous amount of compost and sand added and a very sunny position[
]. Prefers a pH of 5 to 6[
]. Plants are intolerant of water logging[
The young growth in spring, even on mature plants, is frost-tender and so it is best to grow the plants in a position sheltered from the early morning sun[
Kumquats are widely cultivated, especially in China, for their edible fruit. There are many named varieties, and these can usually be divided into two main cultivar groups[
Round Kumquat Group (Formerly known as Fortunella japonica). These are usually trees 2 - 5 metres tall. The orangish yellow to orangish red, globose fruit is 15 - 25mm in diameter with a sweet-tasting skin up to 2mm thick[
Oval Kumquat Group (Formerly known as Fortunella margarita). These are usually trees around 3 metres tall. The orangish yellow to orangish red, ellipsoid to ovoid-ellipsoid fruit is 20 - 35mm in diameter with a sweet-tasting skin around 2mm thick and an acidic flesh in 4 - 5 segments[
Fruit - raw or cooked[
]. They can also be used in jellies, preserves etc or as a flavouring[
]. The whole fruit, including the skin, can be eaten raw - the fruit is very acid whilst the peel has a sweet flavour and the two flavours combine well to make a very tasty food[
]. It is best to first squeeze and massage the fruit in order to combine the flavours of the flesh and the rind[
]. The skin of the round kumquat is golden-yellow, smooth, thinner and somewhat sweeter than that of the oval kumquat[
The fruit is rich in pectin, the inner peel containing about 10%[
]. It makes excellent marmalades and jellies[
]. Vitamin C content is up to 0.24 mg/cc[
After ripening the fruit gradually loses water content, becomes richer in flavour and is then at its best for making preserves[
The bright orange to red, globose to slightly oblate fruit is around 9 - 10mm in diameter in wild forms, and 15 - 35mm in cultivated forms[
The plant is antiphlogistic, antivinous, carminative, deodorant, stimulant[
The fresh fruit is antitussive and expectorant - in Vietnam it is steamed with sugar candy and used in the treatment of sore throats[
]. It is said to be very good for infants[
The leaves and fruit contain an essential oil, whilst the fruit also contains sugars and organic acids[
The fresh leaves and young twigs yield 0.21% essential oil that might be suitable for perfumery[
Seed - best sown as soon as it is ripe in a warm airy position in a greenhouse. When they are large enough to handle, prick out the seedlings into individual pots and grow them on in a greenhouse for at least their first two winters. Plant out in late spring or early summer after the last expected frosts and give some winter protection from the cold for a year or two.