Common Name: Japanese Pepper Tree

General Information

Zanthoxylum piperitum is a prickly, compact, rounded, deciduous shrub growing up to 2 metres tall[, ].
The plant is commonly harvested from the wild, and is also much cultivated in Japan and Korea, for its fruit which is used as a pepper-like flavouring. The plant is also often used as a medicine. It is sometimes grown as an ornamental in gardens.

Known Hazards

None known

Botanical References

, ,

Range

E. Asia - Japan, Korea

Habitat

Scrub and hedges in hills and mountains[, ].

Properties

Edibility Rating
Medicinal Rating
Habit	Deciduous Shrub
Height	2.00 m
Self-fertile	No
Cultivation Status	Cultivated, Ornamental, Wild

Cultivation Details

Zanthoxylum piperitum can tolerate winter temperatures falling occasionally as low as -15°c[].
Easily grown in loamy soils in most positions, but prefers a good deep well-drained moisture retentive soil in full sun or semi-shade[, , ].
A very ornamental plant[].
Flowers are formed on the old wood[].
The bruised leaves are amongst the most powerfully aromatic of all leaves[].
A dioecious species - both male and female forms must be grown if fruit and seed are required. Self-sown seedlings have occasionally been observed growing in bare soil under the parent plant[].

Edible Uses

Seed - cooked. It is ground into a powder and used as a condiment, a pepper substitute[, , , , ]. The fruit can also be used[]. It is often heated in order to bring out its full flavour and can be mixed with salt for use as a table condiment[]. The ground and dry-roasted fruit is an ingredient of the Chinese 'five spice powder'[].
The bark and leaves are used as a spice[, , ].

Young leaves - raw or cooked. They are used in soups or as a flavouring in salads[, , ].

Medicinal

The fruit pericarp is anthelmintic, antibacterial, antifungal, antiperiodic, antitussive, carminative, diuretic, parasiticide, stimulant and stomachic[, ]. It is recommended in the treatment of dysentery, spermatorrhcea, galactorrhoea, and polyuria[]. It is used in Korea in the treatment of tuberculosis, dyspepsis and internal parasites[].
Externally, it is used as a stimulant to the skin and as a parasiticide[].
The fruit pericarps, which are called Chiao-hung. are considered somewhat deleterious if used in quantity or over a long period. Their prolonged use is said to produce imbecility and to injure the blood vessels[]. The fruit inhibits the synthesis of prostaglandin and, in larger doses, is toxic to the central nervous system[].

The leaves have properties similar to those of the pericarps, and are prescribed in similar cases. A decoction of these is recommended in he treatment of varnish poisoning (from Rhus species).

The seeds are considered diuretic, and are used in the treatment of dropsies, diseases of the kidney and bladder, and in asthma[].

The resin contained in the bark, and especially in that of the roots, is powerfully stimulant and tonic[].

A decoction of the root is used in the treatment of kidney and bladder difficulties[].
Used as a wash, the decoction is used to treat ecchymoses and other skin affections[].

The fruit contains an essential oil, flavonoids and isoquinoline alkaloids[].

Other Uses

None known

Propagation

Seed - best sown in a greenhouse as soon as it is ripe in the autumn. Stored seed may requires up to 3 months cold stratification, though scarification may also help[]. Sow stored seed in a cold frame as early in the year as possible. Germination should take place in late spring, though it might take another 12 months. Prick out the seedlings into individual pots when they are large enough to handle and grow them on in a cold frame for their first winter. Plant them out in early summer.
Cuttings of half-ripe wood, mid summer in a frame.
Root cuttings, 3cm long, planted horizontally in pots in a greenhouse. Good percentage[].
Suckers, removed in late winter and planted into their permanent positions[].