Komatsuna Brassica rapa var. perviridis
Komatsuna (Brassica rapa var. perviridis) is an annual vegetable in the Brassicaceae family, native to Japan (cultivar group of Brassica rapa). It grows 30–45 cm (12–18 in) tall and 25–35 cm (10–14 in) wide, wants part sun to part shade and moderate water, and is hardy to about -6 °C (21 °F). Space plants about 20 cm (8 in) apart.
Plan Komatsuna in your garden →
Free. Draw your beds, then watch it grow through the year in 2D and 3D.
Komatsuna at a glance
| Type | Annual vegetable |
|---|---|
| Family | Brassicaceae |
| Mature height | 30–45 cm (12–18 in) |
| Mature spread | 25–35 cm (10–14 in) |
| Spacing | 20 cm (8 in) centre to centre |
| Sun | Part sun to part shade, at least 4 h of direct sun a day |
| Water | Moderate; drought tolerance none, waterlogging tolerance low |
| Soil pH | 6–7 |
| Cold hardiness | About -6 °C (21 °F) once established (roughly USDA zone 9) |
| Heat stress | Likely above about 28 °C (82 °F) |
| Flowering | about 11–17 weeks after planting, for 4–6 weeks |
| Days to maturity | About 40 days from planting |
| Wind tolerance | Low |
| Pollinator value | Moderate |
| Edible | Yes: leaves, stems |
| Native to | Japan (cultivar group of Brassica rapa) |
| Common in gardens of | 🇯🇵 Japan |
Is Komatsuna toxic?
- People: not known to be toxic
- Cats: not known to be toxic
- Dogs: not known to be toxic
Not toxic; raw brassicas can cause gas in pets if eaten in quantity.
If a child or pet may have eaten part of a plant, call a poison centre or vet straight away.
Companion planting: what to grow with Komatsuna
Good neighbours
- good With Rhubarb: Traditional lore says rhubarb planted near brassicas helps against clubroot and pests; the evidence is weak and not confirmed by trials. Evidence D
- good With Nasturtium: Nasturtiums act as a trap crop for cabbage white butterflies and blackfly, drawing some pressure away from brassicas. Evidence C
Shared pests and diseases
- Clubroot: Clubroot spores persist in soil up to 20 years; keep brassicas in a rotation. Evidence B
Questions about Komatsuna
- How far apart should I plant Komatsuna?
- About 20 cm (8 in) apart, centre to centre. A mature plant spreads 25–35 cm (10–14 in).
- Does Komatsuna need full sun?
- Part sun to part shade: at least 4 hours of direct sun a day.
- How much water does Komatsuna need?
- Moderate water. Drought tolerance is none and waterlogging tolerance low.
- How cold-hardy is Komatsuna?
- It tolerates about -6 °C (21 °F) once established, roughly USDA zone 9. As an annual it is usually planted out after the last frost.
- When does Komatsuna flower?
- About 11–17 weeks after planting, for 4–6 weeks.
- Is Komatsuna poisonous to cats and dogs?
- For cats it is not known to be toxic; for dogs not known to be toxic; for people not known to be toxic. Not toxic; raw brassicas can cause gas in pets if eaten in quantity.
- What grows well with Komatsuna?
- Traditional lore says rhubarb planted near brassicas helps against clubroot and pests; the evidence is weak and not confirmed by trials. Nasturtiums act as a trap crop for cabbage white butterflies and blackfly, drawing some pressure away from brassicas.
Sources and evidence
Evidence grade C (C: plausible, mixed evidence).
- University extension gardening guides (general), Various land-grant university extensions
- EcoCrop crop environmental requirements, FAO
- RHS Plant Finder, Royal Horticultural Society
Notes and assumptions
- Relatively slow to bolt compared with other Asian greens; sown spring to autumn.
Reference values for planning, not horticultural, veterinary or medical advice. Varieties, soils and local climates differ: check with a local nursery or extension service.
Related plants
- Broccoli Brassica oleracea var. italica
- Cauliflower Brassica oleracea var. botrytis
- Cabbage Brassica oleracea var. capitata
- Kale Brassica oleracea var. sabellica
- Radish Raphanus sativus
- Bok choy Brassica rapa subsp. chinensis
- Brussels sprout Brassica oleracea var. gemmifera
- Kohlrabi Brassica oleracea var. gongylodes