Eutrema japonicum Koidz.

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.

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.

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.

Can be grown by divisions or seedlings.