Common Name: Japanese Raisin Tree

General Information

Hovenia dulcis is a deciduous tree with a fairly open, upright, oval crown, occasionally no more than a shrub; it can be up to 15 metres tall[].
The tree is harvested from the wild for local use as a food, medicine and source of materials. It has gained a high reputation for protecting the liver from alcohol damage, and is cultivated for its fruit in Japan and China[]. The plant is sometimes also grown as an ornamental.

Known Hazards

None known

Botanical References

, ,

Range

E. Asia - China to the Himalayas.

Habitat

Plains and mountains; at elevations up to 2,000 metres in W. China[]. Secondary forest; at elevations from 200 - 1,400 metres[].

Properties

Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Deciduous Tree
Height	8.00 m
Cultivation Status	Cultivated, Ornamental, Wild

Cultivation Details

Although the dormant plant is hardy to at least -15°c in maritime climates such as Britain, Hovenia dulcis really prefers a continental climate to fully ripen its wood, it is then hardy to about -25°c[]. The shoot tips are sometimes damaged by late winter frosts[] and the young growth in spring can also be damaged by even quite light frosts[].
Grows well in a fertile sandy loam in a sunny position[]. Succeeds in full sun to moderate shade, tolerating a wide range of soils so long as they are well-drained.
The Japanese raisin tree is said to grow well in Cornwall[], though our experience of this plant so far (1995) is that it is very difficult to establish. Perhaps older plants are as hardy as the reports above suggest, but younger plants are quite tender and often die in their first few winters outdoors[].
The Japanese raisin tree is cultivated for its edible fruit in Japan.
The small white flowers are scented and are produced in terminal cymes[].

Edible Uses

Fruit - raw or cooked[, , ]. The fleshy rachis of the infructescence is sweet and edible and is also used for making wine and candy[]. They can be dried when they have the sweet flavour and texture of raisins and can be used similarly[]. The fruit is sweet and fragrant[, ] with a pear-like flavour[]. Dry and sub-acid[]. It is not a true fruit but a swollen receptacle[]. The fruit is up to 3cm long[], it contains 11.4% glucose, 4.7% fructose and 12.6% sucrose[].

A sweet extract of the seed, boughs and young leaves is used as a substitute for honey[]. The seed contains 15% protein and 7.8% fat[].

Medicinal

The fruit is antispasmodic, febrifuge, laxative and diuretic[, ].
Both the fruits and the fleshy peduncles are considered to be antifebrile, diuretic, hepatic, laxative and quieting to the stomach[, ]. Remarkable antivinous properties are also attributed to them - it is said that after the ingestion of large quantities of alcohol the use of this plant will prevent any intoxicant or poisonous action[, ].
Research has shown that the plant has an effect on reducing blood sugar levels and also exerts a protective influence over the liver - it is most effective if taken 30 minutes before the ingestion of alcohol (when it can reduce levels to 17% of control), though it is also somewhat effective if taken at the same times as alcohol (to 50% control levels), and also has some effect if taken after alcohol.

The seeds are diuretic and are used in the treatment of alcohol overdose[]. The seeds are used to relieve intoxication due to wine[].

The stem bark is used in the treatment of rectal diseases[, ].

Other Uses

The timber is fine-grained and hard; it is used for building construction and fine furniture[].

Propagation

Seed - germinates freely if sown as soon as it is ripe in a cold frame[]. Stored seed should be scarified and sown in early spring[], it may not germinate for a year. Prick out the seedlings into individual pots when large enough to handle and grow on for at least their first winter in a greenhouse. Plant out in late spring after the last expected frosts and give some winter protection for their first couple of years outdoors.
Cuttings of half-ripe wood, mid summer in a frame[].
Cuttings of mature wood, late autumn in a frame[].