Japanese Horseradish, Wasabi

Wasabia japonica

Physical Characteristics

Wasabia japonica is a PERENNIAL growing to 0.3 m (1ft) by 0.2 m (0ft 8in). See above for USDA hardiness. It is hardy to UK zone 8. It is in flower from April to May. The species is hermaphrodite (has both male and female organs). Suitable for: light (sandy), medium (loamy) and heavy (clay) soils. Suitable pH: mildly acid, neutral and basic (mildly alkaline) soils. It can grow in semi-shade (light woodland) or no shade. It prefers wet soil and can grow in water.

Distribution

E. Asia - Japan.

Habitats

Pond; Bog Garden;

Edible Uses

Edible Parts: Leaves Root Edible Uses: Condiment Root - a horseradish substitute[2, 46, 58, 61, 105]. The fleshy rhizomes are finely grated and prepared into an attractive fresh green paste which is much used as a condiment in Japan[183]. It is considered to have a distinct flavour and pungency that is superior to horseradish, Armoracia rusticana[183]. The pungency rapidly deteriorates once the root has been cut[200]. Roots of plants 15 - 24 months old are best[238]. Leaves, flowers and petioles - cooked[105, 179, 200]. The leaves, flowers, leafstalks and freshly sliced rhizome are soaked in salt water and then mixed with saki lees to make a popular Japanese pickle called 'wasabi-zuke'[183]. The following analysis is said to belong to the leaves but it looks more like a root analysis[K]. The leaves contain about 6.1% protein, 0.2% fat, 22.3% carbohydrate, 1.3% ash[179].

Medicinal Uses

Digestive The root is a pungent warming herb that stimulates the digestion[238]. It is used internally as an antidote to fish poison[238]. (This probably refers to food poisoning caused by eating fish[K]).

Known Hazards

None known