Wasabi, Japanese horseradish
Eutrema japonicum

Family: Brassicaceae

What it is like

A cabbage family herb. It is a small plant which grows up to 40-60 cm high. It keeps growing from year to year. The plant has a stout rhizome. It has thick stems. It is knobbly and grey-green. The leaves are crinkled and heart shaped. They are like pumpkin leaves. The flowers are small and white. They have 4 petals. The fruit are long narrow seed pods.

Chemical composition: Protein = 5.1%. Fat = 0.2%. Carbohydrate = 22.3%. Ash = 1.27%. The main compound causing the pungent taste is sinigrin.

Where it is found

It is a temperate plant. It grows beside cold mountain streams. The small roots grow best in clear streams. It needs good aeration around the roots. Wasabi requires cool shady conditions. It is cultivated, also naturalised in wet areas along streams in mountains; near sea level to 2500 m altitude in China.

Countries/locations it is found in

Asia, Australia, China, Japan, Korea, New Zealand, North America, Russia, Taiwan, Tasmania, USA

How it is used for food

The underground stems or rhizomes are used as a spice called wasabi. It has a strong fiery taste. The outer skin is scraped off and the green inner part finely ground. The leaves, flowers are leaf stalks and freshly sliced rhizome are soaked in salt water then used to make a pickle.

It is a cultivated food plant.

Edible parts

Leaves, stalk, root, rhizome, vegetable, spice

How it is grown

The rhizomes take 2-3 years to develop. The rhizome should be used fresh as it quickly loses its flavour.

Its other names

Local names

Asian horseradish, Kuai jing shan yu cai, Mountain hollyhock, Raifort du japon, Shan yu cai

Synonyms

Alliaria wasabi (Siebold) Prantl; Cochlearia wasabi Siebold, Verh.; [Invalid] Cardamine bracteata S. Moore (1878), not Philip-pi (1893), nor Suksdorf (1918); ? Eutrema bracteatum (S. Moore) ? Eutrema japonicum (Miquel) Koidzumi; Eutrema koreanum (Nakai) K. Hammer; Eutrema okinosimense Takenouchi; Eutrema wasabi Maxim.; Eutrema wasabi var. sachalinensis Miyabe & T. Miyake; Lunaria japonica Miquel; Nasturtium tenue Miquel; ? Wasabia japonica (Miquel) Matsumura; Wasabia koreana Nakai; Wasabia okinosimensis (Taken.) Hatus; Wasabia pungens Matsumura; Wasabia wasabi (Siebold) Makino.