Japanese horseradish (Wasabia japonica)

Other names wasabi

Japanese horseradish (Wasabia japonica)
Wikimedia Commons — Qwert1234 — CC BY-SA 3.0 (https://creativecommons.org/licenses/by-sa/3.0)

At a glance

Lifecycle
Perennial (hardy)
Exposure
Full sun
Frost limit
−12.2 °C

Cultivation

Prefers a position in wet soil or shallow water. The best quality roots are produced from plants growing in semi-shade in clear running spring water at a temperature between 11 - 14°c. This species is cultivated in eastern Asia for its edible root which is used in much the same way as horseradish.

Propagation

Seed - sow spring in a greenhouse and keep the seed permanently moist. Prick out the seedlings into individual pots when they are large enough to handle and grow them on in the greenhouse for their first year. Stand the pots in shallow water to ensure the plants do not dry out. Plant them out in late spring or early summer. Division in spring as the plant comes into growth. Very easy, the larger divisions can be planted out direct into their permanent positions. We have found that it is best to pot up smaller divisions and grow them on in light shade in a greenhouse or cold frame until they are growing away well. Plant them out in the summer or the following spring.

Edible uses

Root - a horseradish substitute. Leaves, flowers and petioles - cooked.

Medicinal uses

The root is a pungent warming herb that stimulates the digestion. (This probably refers to food poisoning caused by eating fish[K]).

Habitat

Wet places and by streams, in lowland and mountain areas.

Native range

E. Asia - Japan.

Scientific synonyms Eutrema japonicum