Wasabi
Eutrema japonicum
A mountain-stream plant grown for its pungent green stem; it needs deep shade, cool air and constant fresh moisture.
Hardiness: zones 8 to 10
Light: shade
Size: about 1.5 ft tall, 1.5 ft wide
Harvest: year-round
From: Japan
Here: Too tender to overwinter outdoors on the Lake Erie shore (zone 6b to 7a): grow it in a pot and bring it in, or treat it as an annual.
Good for: food.
Native to: East Asia, Japan & its islands. Hardy in zones 8 to 10.
The story
Wasabi grows wild beside cold mountain streams in Japan and has been cultivated since at least the 1600s in the gravel beds of Shizuoka. Most of the green paste sold abroad is coloured horseradish; the real stem is grated fresh at the table.
Planting
Deep shade, cool temperatures all year and soil that is always moist but never stagnant. A pot in a shady, sheltered spot suits it.
Growing
It dislikes summer heat and winter frost alike. Feed lightly and divide the offshoots.
Harvest and use
The swollen stem takes about two years. Grate it finely just before eating; the flavour fades in minutes. Leaves and stalks are pickled.
What to watch for
Heat, direct sun and slugs. It is one of the harder crops to please.
See if Wasabi fits your yard
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More perennial vegetables, greens and herbs
General guidance, not professional advice. Conditions vary by yard and year; for local specifics ask your county extension office. Never eat a wild plant you cannot identify with certainty. Traditional uses are shared as history, not medical advice. © 2026 Sean Priest · Irie Orchard. Terms & credits · Privacy · Home