Komatsuna (Japanese mustard spinach)
Brassica rapa var. perviridis
Tender, mild greens named for a river near old Edo; quick from seed in spring and autumn, and hardy under snow.
Hardiness: zones 3 to 10
Light: full sun to part shade
Size: about 1.5 ft tall, 1 ft wide
Harvest: April to November
From: Japan
Here: Hardy in the Lake Erie shore climate (zone 6b to 7a), so it can live outdoors in the ground.
Good for: food.
Native to: East Asia. Hardy in zones 3 to 10.
The story
Komatsuna takes its name from the Komatsu River district of old Edo, now Tokyo, where it has been grown for centuries. It is a New Year green in Japan, simmered in the soup called ozōni.
Planting
Sun or light shade and moist soil. Sow directly from early spring to autumn, a little every few weeks.
Growing
It is ready in a month. Water in dry spells so it stays mild.
Harvest and use
Cut whole plants or pick outer leaves. Use raw when small, stir-fried or in soup when larger.
What to watch for
Flea beetles pepper the leaves in summer. Heat sends it to flower.
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More annual vegetables, herbs and grains
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