Cercis chinensis Seeds | Chinese Redbud
LATIN NAME: Cercis chinensis
COMMON NAME: Chinese Redbud
Plant Profile
Cercis chinensis flowers on bare wood in early spring, and the flowers come out of the trunk and the old branches as well as the twigs. The pea-shaped blooms are a deep pink-purple, carried in tight clusters along the bark, and they open before the leaves, so the whole shrub looks as though it has been wired with colour. The habit is a large shrub or a small tree to about eight metres.
The species grows on limestone hills in central and eastern China, often in scrub and at the edge of woodland. The leaves are round, glossy and heart-shaped, with a pointed tip, and they turn yellow in autumn. The pods that follow are flat and thin, and they ripen in late summer, when the seed inside turns brown and hard.
Science & Biotechnology
Cercis belongs to the legume family but does not nodulate. It has no root nodules and no rhizobial partnership, so it depends on mycorrhizal fungi and on leaf litter for nitrogen, and it grows best on soils where those fungi are present. The tree also tolerates limestone, which is unusual in a genus that is otherwise woodland-based.
The cauliflory, the flowering on old wood, is a mechanical solution to a timing problem. The buds are formed the previous summer and held under the bark, and the trunk has enough stored carbohydrate to open them before the leaves can supply any. That is why a hard-pruned plant flowers poorly: the wood that carries the buds has been removed, and the plant needs several years to rebuild it.
Uses & Benefits
The plant is grown as an ornamental for the early flowers, and it is used in China as a street tree and in temple courtyards. The bark and the wood are used in Chinese medicine, where the species is known as zi jing, for menstrual complaints and for bruising, and the wood is hard and used for small turnery.
In China the flowers are eaten in salads and the young pods are cooked as a vegetable, though the mature seed is bitter and should not be eaten. The plant is also used as a rootstock for other redbuds in colder climates, since it is hardier than the American species.
Growing from Seed
Seed needs scarification. Pour hot water over it, leave it to soak for a day, and sow the swollen seed in a free-draining mix at 20 degrees. Germination is in three to six weeks, and untreated seed can sit for a year. Cuttings are difficult, and named forms are usually grafted.
The plant wants full sun and a well-drained soil, and it tolerates lime and drought once established. It is hardy to about minus twenty, but late frost damages the open flowers, so a site that holds cold air is a poor choice. Prune only to remove dead wood and to shape the plant when young, since the flowers are carried on old stems.
Our Take
A redbud for a cold garden, flowering on the trunk before anything else has opened, and best left unpruned so the old wood can carry the buds.
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