Crop type: Chinese Cabbage
Brassica rapa (Pekinensis Group) ‘Wa Wa Sai’
Common name: Chinese cabbage ‘Wa Wa Sai’
Crop slug: chinese-cabbage
This Allotment Pro editorial draft summarises the cited RHS cultivar profile. Check the source and adjust cultivation decisions for local conditions.RHS cultivar profile
1 - Overview
‘Wa Wa Sai’ is a very fast-growing small Chinese cabbage with a compact, uniform habit. It can be planted closely in a small patch, where its green leaves and clean white veins form tender edible heads without demanding the space of a large barrel cultivar.
The leaves are notably sweet and tender while retaining a satisfying crunch. This combination of speed, small size and eating quality makes the cultivar useful for containers, raised beds and succession sowings. ‘Wa Wa Sai’ holds the RHS Award of Garden Merit.
2 - Size
- Ultimate height
- 0.1–0.5 metre
- Ultimate spread
- 0.1–0.5 metre
- Time to ultimate size
- 1 year
Its compact tufted form permits closer planting than large-headed Chinese cabbages. Leave enough space for each small green-and-white head to close without becoming damp or congested.
3 - Growing conditions
- Suitable soils
- Chalk, clay, loam and sand
- Moisture
- Moist but well-drained
- Soil pH
- Acid, neutral or alkaline
Prepare firm fertile ground with dependable moisture and free drainage. Although adaptable across common soil textures and pH ranges, the rapidly growing leaves perform best without drought or waterlogging.
4 - Position and hardiness
- Light
- Full sun
- Aspect
- East-, north-, south- or west-facing
- Exposure
- Exposed or sheltered
- Hardiness
- H5 — hardy in most UK locations, including severe winters at approximately −15 to −10°C
The profile includes coastal cultivation and both exposed and sheltered sites. Full sun, fertile soil and regular water remain important for producing the tender, sweet heads for which the cultivar is selected.
5 - Colour and seasonal interest
The plant makes a compact green head patterned by strong white veins. Its visual appeal comes from the even, uniform tuft and the crisp contrast between tender green blades and pale ribs rather than from flowers or fruit.
6 - Botanical details
- Family
- Brassicaceae
- Native to Great Britain and Ireland
- No
- Foliage
- Evergreen
- Habit
- Tufted
- Name status
- Unresolved
Genus
Brassica includes annual, biennial and perennial plants with alternate, often glaucous leaves, long taproots and cross-shaped yellow or white flowers. It contains many vegetables bred for edible leaves, stems, roots and seed.
7 - How to grow
Cultivation
Grow in full sun in firm, fertile soil, including in coastal regions. Sow seed in small batches and use the cultivar’s compact scale to fit several heads into a productive patch, while preserving enough airflow around the tufted leaves.
Water through dry spells so the very fast-growing foliage remains sweet and tender. Harvest once the compact head is well filled but still crisp, or take selected outer leaves while preserving the central growing point.
Propagation
Propagate by seed.
Pruning
No pruning is required. Remove damaged leaves only and harvest the edible head cleanly at its base.
Pests
May be susceptible to flea beetle while young, small white butterfly caterpillars, cabbage root fly, mealy cabbage aphid and pigeons. Fine mesh protects the close-planted crop and helps keep the tender leaves intact.
Diseases
May be susceptible to brassica downy mildew and brassica white blister. Club root may accumulate in ground used repeatedly for brassicas, so rotate crops and use clean growing media in containers.