Natural form

Choy sum bundles showing slender stems, tender green leaves, and small yellow flowers.

Shows the plant's defining visual identity — the yellow flowers that distinguish choy sum from other Chinese greens.

Produce

Choy Sum

Tender leafy green with yellow flowers, quickly blanched or stir-fried in Cantonese cooking.

Choy sum is a leafy Chinese green with slender stems, green leaves, and small yellow flowers, sweeter and more tender than its relatives. It is blanched and dressed with oyster sauce or stir-fried with garlic, cooking in just a couple of minutes. A everyday vegetable across Cantonese and Southeast Asian kitchens.

Choy sum (Brassica rapa var. parachinensis) is a tender leafy green vegetable central to Cantonese and broader Southern Chinese cooking. Distinguished by hollow stems, smooth dark-green leaves, and edible yellow flowers, it belongs to the same species complex as bok choy and gai lan but stands apart through its exceedingly slender stalks and delicate, almost succulent texture. The entire plant is edible—stems, leaves, and flowers alike—requiring only the briefest encounter with heat to transform from raw to perfectly cooked. In Cantonese culinary tradition, choy sum is classified as a fundamental 'green vegetable' (ching chaan), served alongside rice and protein to create a balanced meal. Its mild bitterness and subtle sweetness complement rich, savory sauces without overpowering them, making it one of the most reliable vegetables in the Cantonese repertoire. The flowers not only add visual appeal—bright yellow punctuating glossy green—but also a faint sweetness that signals the vegetable's freshness when barely open.

Measured in: g
Storage: Fridge

Types & varieties

Early choy sum

Harvested at 25–30 days; thinner stems, more delicate, ideal for quick blanching or raw applications

Mid-season choy sum

Harvested at 35–45 days; medium stem thickness, the workhorse variety for most restaurant and home use

Late choy sum

Harvested at 50+ days; thicker stems, stronger flavor, more prone to fiber—peel outer layers before cooking

Jie lan (ciliate mustard)

Often conflated with choy sum in markets; distinguished by slightly serrated leaf edges and a more pronounced mustardy bite

Distinguishing Choy Sum from Similar Greens

Choy sum's tender hollow stems set it apart from gai lan (Chinese broccoli), which has solid, thick, and noticeably more fibrous stems requiring longer cooking. Bok choy, while also having hollow stems, produces a denser, heavier stalk with a different texture altogether. When shopping, look for plants with bright yellow flowers that are still tight buds—open flowers indicate age, and the stalks will be coarser. The stems should feel snap-fresh, not bendy or wilted. Some markets sell choy sum with roots intact; these roots are edible but need significantly more cooking time or should be trimmed off for standard preparations.

Hollow stems vs. solid stems (gai lan)
Edible flowers vs. flower buds that may be removed
Slender stalks vs. thicker, denser bok choy

Common uses

Blanched with oyster sauce as a Cantonese restaurant staple, served alongside any proteinStir-fried with garlic and ginger for a simple home-style side dishAdded to claypot rice (bao fan) in the last 5 minutes of cookingWok-fried with preserved eggs for a classic Cantonese combinationHot pot and shabu-shabu ingredient; briefly dipped in bubbling broth for 15–30 secondsSteamed whole and dressed with sesame oil, soy sauce, and a drizzle of heated oilStirred into congee or jook near the end of cooking to add color and nutritionFinished with fermented bean curd for a bold, savory variation

Tips & pitfalls

Buy choy sum before flowers fully open—open flowers indicate older, coarser stalks that have passed their prime
Wash thoroughly by separating individual stalks and rinsing between leaves; soil collects at the base and in leaf crevices
Never overcook: stems should retain a slight snap. Blanch 30–60 seconds; stir-fry 1–2 minutes maximum
Select smaller specimens (10–15 cm) for tenderness; larger stalks become stringy and fibrous
Chinese supermarkets often sell choy sum with roots attached; trim roots for standard dishes or cook them separately for longer preparations
If stems feel thick and woody, peel the outer fibrous layer with a knife before cooking—this step transforms late-season choy sum
Season blanching water generously with salt to set the bright green color and add baseline seasoning to the vegetable itself
For stir-frying, ensure your wok is properly heated and smoking before adding oil and vegetables; cold wok equals soggy greens

Nutrition

13kcal

Energy

54 kJ · per 100 g

Where the calories come from

Protein 36%Carbs 53%Fat 11%

Protein

1.5g

3% DV

Carbs

2.2g

1% DV

Fat

0.2g

0% DV

Fiber

4% DV

Sugars

1.2g

of which

Sodium

65mg

3% DV

Notable micronutrients

Vitamin C50% DV

Vitamin K38% DV

Vitamin A25% DV

Folate17% DV

Vitamin B611% DV

Calcium8% DV

Source · USDA FoodData Central · Cabbage, chinese (pak-choi), raw

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In the shops

Matched grocery products

No matched grocery products for Choy Sum yet.

Good to know

Botanical name: Brassica rapa var. parachinensis (also cited as B. chinensis)
Primary cuisine: Cantonese
Edible parts: Stems, leaves, and yellow flowers
Stem character: Hollow, slender, and tender when young
Cooking principle: High heat, minimal time—30 seconds to 2 minutes maximum
Seasonality: Available year-round; best in cooler months when stalks remain tender

Substitutes

Gai lan (Chinese broccoli) — Stems are thicker and more fibrous; blanch 30 seconds longer and consider peeling outer layers
Bok choy — Denser stems work in stir-fries but lack the tender flower stalks and delicate character of choy sum
Baby bok choy — More succulent stems with similar cooking time; acceptable substitute when choy sum is unavailable

Pairs with

Oyster sauce Garlic Sesame oilPreserved eggs (皮蛋)Dried shrimp (虾米)Ginger

Also called

Sawi · Cai Xin · Chinese Flowering Cabbage