Dendrobenthamia japonica Seeds | Japanese Dogwood
LATIN NAME: Dendrobenthamia japonica
COMMON NAME: Japanese Dogwood, Kousa Dogwood
Plant Profile
Japanese Dogwood, sold in older books as Dendrobenthamia japonica and in modern floras as Cornus kousa, is a small tree of Japan, Korea and eastern China, growing slowly to six or eight metres. In June, after the native cherries have finished, it covers itself with four-pointed white bracts that are often mistaken for petals.
By autumn the flowers have become raspberry-like, knobbly fruits hanging on long stalks, the leaves turn crimson, and the mottled bark peels in patches to show tan and cream beneath. It is one of the few trees that earns its space in all four seasons without a companion. Older trees develop horizontally tiered branches that hold their shape without pruning, and the branching habit is one of the traits breeders select for in compact garden forms.
Science & Biotechnology
The white show is not the flower: the true flowers are the small greenish heads in the centre, and the four points are modified leaves called bracts, an arrangement shared with the North American flowering dogwood. Unlike that species, Cornus kousa has shown good resistance to the anthracnose that has devastated American dogwood woods since the 1980s, which is one reason plant breeders have crossed the two.
The fruits are edible when soft, sweetish and pulpy, though the skin is bitter; they are sold in markets in Japan and are the origin of several ornamental selections grown for heavy crops.
Uses & Benefits
In the garden it is a specimen for a lawn edge or a woodland garden in full sun to light shade, on soil that stays cool and slightly acid. It flowers on mature wood, so a young tree needs several years of undisturbed growth before the first full display.
The late nectar and the autumn fruits make it useful for wildlife, and its disease resistance has made it the dogwood of choice in districts where the flowering dogwood has failed. The June bracts hold for three weeks or more, longer than any cherry, and the tree flowers even in years when a late frost has checked other spring displays. Its bark pattern alone is reason enough to plant it by a path: in winter the trunk reads like camouflage cloth, and low branches can be trained to show it off.
Growing from Seed
The seed needs two cold periods: clean the flesh from the fruit and give it a warm, moist month followed by three to five months at just above freezing before sowing.
Sow half a centimetre deep in a lime-free compost and keep it cool and shaded; germination is slow and often spreads over a second spring, so keep the tray watered and do not discard it.
Grow the young trees in partial shade for two or three years, pot on each spring, and move them to their final position while they are small, since older plants transplant poorly.
Our Take
A four-season small tree: June bracts, knobbly autumn fruits, crimson leaves and patterned bark, well worth its slow start from seed.
Related Reading
Gardeners who grow Japanese Dogwood often pair it with these related subjects: