Choy sum
Leafy vegetable with yellow flowers, used in Chinese cuisine.
Choy sum (also spelled choi sum or choi sam in Cantonese; caixin in Standard Mandarin) is a leafy vegetable commonly used in Chinese cuisine. It is a member of the genus Brassica of the mustard family, Brassicaceae, and is also known as Chinese flowering cabbage.
- also_known_as
- Chinese flowering cabbage
Lore & Background
Choy sum is a green leafy vegetable similar to gai lan, characterized by distinct yellow flowers, each with four yellow, oval to round petals and six stamens on fleshy, erect stems. The stems are 0.5 to 1 cm in diameter and 15 to 20 cm tall, with light to dark green oval leaves that become acuminate or basal-shaped near flowering, with slightly serrated margins. The plant never forms compact heads like cabbage. Fruits develop from cross-pollination or self-pollination and are silique-structured, opening at maturity through dehiscence to release small, round brown or black seeds; a single pod can bear 4 to 46 seeds.
Reader's Guide
Choy sum is highly valued as a vegetable in China and Japan, commonly consumed in soup, blanched, or stir-fried. The plant is an annual, herbaceous plant, rarely perennial or subshrub, with a simple or branched leafy structure. It grows best in soil with a pH between 5.6 and 7.5. The bulk of its root system is found within a depth of 12 cm and confined to a radius of 12 cm. Flowering usually appears when the plant has about 7 to 8 leaves or is about 20 cm tall. The height varies from 10 to 40 cm depending on growing conditions and variety. Its significance lies in its widespread use in East Asian cuisine and its botanical characteristics as a Brassica species.
Did You Know?
- Choy sum is a transliteration of the Cantonese name, which literally translates as 'heart of the vegetable'.
- Each flower has four yellow, oval to round petals with six stamens.
- A single pod can bear 4 to 46 seeds.
- The plant grows best in soil with a pH between 5.6 and 7.5.
Frequently Asked Questions
What is Choy sum?
Choy sum is a tender leafy green vegetable from the mustard family, widely used in Chinese cooking. It is also commonly called Chinese flowering cabbage, yu choy, or you cai depending on the region.
What is Choy sum's scientific classification?
It sits within the genus Brassica of the Brassicaceae (mustard) family, and is formally identified as either Brassica rapa var. parachinensis or Brassica chinensis var. parachinensis.
What does Choy sum look like and how big does it grow?
The plant typically reaches between 10 and 40 cm (roughly 4 to 16 inches) in height and is topped with small, bright yellow blossoms. Each seed pod contains anywhere from 4 to 46 seeds.
How is Choy sum used in the kitchen?
It is a staple green in Chinese cuisine, most often stir-fried, steamed, or dropped into broth-based soups. The tender stems, leaves, and even the little yellow flowers are all edible and commonly eaten together.
What other names does Choy sum go by?
You will see it spelled choi sum or choi sam in Cantonese contexts, and caixin in Standard Mandarin. In English-language recipes and markets it frequently appears as yu choy, you cai, or simply Chinese flowering cabbage.
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