Hovenia dulcis Seeds | Japanese Raisin Tree

Twisted reddish raisin-like fruit stalks hanging among glossy heart-shaped leaves — Japanese Raisin Tree (*Hovenia dulcis*): Rhamnaceae, warm hills of China, Korea and Japan.

LATIN NAME: Hovenia dulcis

COMMON NAME: Japanese Raisin Tree

Plant Profile

Japanese raisin tree is a deciduous tree of ten to twenty metres with glossy, heart-shaped leaves and small greenish flowers in summer. Its real fruit is a dry, hard capsule, but the stalk that carries it swells after flowering into a fleshy, twisted, reddish-brown morsel with a sweet, fig-like taste, and that is what the tree is grown for. It is native to warm hills of China, Korea and Japan, and it has become a serious invasive tree in southern Brazil. The bark is grey and shallowly fissured, and the crown is broad and open enough to cast a light, dappled shade.

Science & Biotechnology

The swollen stalks are peduncles, not fruit, and their sweetness is largely sucrose with a contribution from dihydromyricetin, DHM, a flavonoid that has become one of the most studied natural compounds in alcohol research. DHM appears to accelerate acetaldehyde clearance and to reduce the acute effects of alcohol in animal models, which is why the tree is the basis of a well-known East Asian hangover remedy. The species is also a prolific seeder, and in the Araucaria forests of Brazil it is now a recognised invader. Its wood anatomy and its floral development have both been described, the latter because the swelling of the peduncle is unusual among trees.

Uses & Benefits

The stalks are eaten fresh and used in traditional medicine, and the seeds are a recognised herbal drug in China, where they are used for hangover and liver complaints under professional guidance. The wood is hard, pale and used for furniture and small turnery. In the garden it is a fast, tolerant shade tree with an autumn party trick, and it is one of the few trees that gives a harvest children will eat straight from the branch. The stalks are also dried and used in Korea as a sweetening for tea and for a traditional rice drink. In Japan the wood is used for small chests and for the handles of tools, and the tree is planted around temples for shade.

Growing from Seed

Clean the pulp from the seed and stratify it at two to five degrees for two to three months, or sow outdoors in autumn. Sow in spring in a free-draining mix and expect germination in four to six weeks. The seedling is fast and unfussy. Plant out in full sun and deep soil, allow ten metres of crown, and prune in winter if a low picking crown is wanted. In warm climates, remove the seed heads before they ripen, because the species seeds itself into any disturbed ground and is hard to remove once established. It also coppices well, so a tree can be cut for poles and brought back for fruit.

Our Take

A shade tree that grows raisins on its branches, and a warning about what happens when it leaves home. Grow it where it belongs, and pick the stalks in October.

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