Stachys affinis aka Chinese Artichoke

Stachys affinis is a tuber-forming perennial in the mint family, Lamiaceae. Gardeners know it as Chinese artichoke, chorogi, or crosnes. Other names include Japanese artichoke and knotroot. Its native range runs from China to Myanmar. Records from China cover many provinces, including Gansu, Hebei, and Sichuan. Wild plants grow in wet places, including sites under water. They occur from low ground to high mountain sites.

This plant forms clumps and loses its leaves each year. The RHS describes plants around 2 feet (0.6 m) tall. Its broader garden range reaches 1.6–3.3 feet (0.5–1 m). Clumps spread about 0.3–1.6 feet (0.1–0.5 m) wide. Plants reach their full size within one or two years. The stems have four angles. Fine hairs cover the textured leaves. Purple-pink flowers rise on upright stalks in summer. Below ground, the plant makes small, knobbly tubers.

Grow it in full sun with shelter from exposed conditions. Give it fertile soil with plenty of humus. Keep the soil moist, but allow excess water to drain. It suits chalk, clay, loam, and sand. Acid, neutral, and alkaline soils all fall within its range. Plant the tubers in spring, and divide clumps to make more plants. The RHS gives it a hardiness rating of H7. PFAF lists USDA zones 4–8. It needs no pruning and suits beds, borders, and informal gardens.

The tubers provide its main food crop. Eat them raw, cook them lightly, or pickle them. Their mild, nutty taste recalls artichokes. Each tuber measures about 0.16–0.26 feet (0.05–0.08 m) long. Their small size can make preparation fiddly. Exposed tubers soon darken, and peeling may reduce their flavour. Harvest them from November, taking only what you need. This avoids keeping a large crop after lifting. Cooked leaves have served as emergency food, rather than a usual vegetable.

Slugs may attack plants, but the RHS reports few disease problems. PFAF lists no known hazards. That report does not establish safety for every possible use. PFAF also records traditional medicinal uses of the root and whole plant. These include pain relief and treatment of colds and pneumonia. Such records describe past use, not proof that these treatments work.