Bok choy

Bok choy (Brassica rapa subsp. chinensis, synonym B. chinensis) is an annual or biennial herb of the mustard family (Brassicaceae) with a short stem, forming a 15–30 cm rosette-like cluster without a head. The leaves spread out, spoon- to round-shaped, glossy dark green; the leaf stalks are thick, plump, ivory-white or pale-green, crisp and juicy, packed tightly into a rosette. When it bolts, a terminal cluster of small four-petalled pale-yellow flowers appears, typical of the mustard family; the fruit is a long silique bearing small round brown seeds. The whole plant is edible, mild and sweet, and cooling.

Bok choy originates in China, cultivated for thousands of years and spread across East and Southeast Asia; in Vietnam it is a common vegetable grown year-round in the lowlands and midlands. It is a short-cycle crop (30–50 days), easy to grow, high-yielding and less troubled by pests than cabbage. In cuisine, bok choy is stir-fried with garlic, boiled, steamed, used in noodles, hotpot and eaten fresh; the white stalks are crisp and the green leaves tender. Nutritionally it is rich in vitamins C, K and A, folate, calcium and fibre, low in calories — a healthy vegetable good for bones and digestion.