Wasabi Eutrema japonicum
Wasabi (Eutrema japonicum) is an evergreen perennial vegetable in the Brassicaceae family, native to Mountain streams of Japan and Sakhalin. It grows 30–50 cm (12–20 in) tall and 30–60 cm (12–24 in) wide, wants shade and high water, and is hardy to about -5 °C (23 °F). Space plants about 30 cm (12 in) apart.
Plan Wasabi in your garden →
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Wasabi at a glance
| Type | Perennial vegetable, evergreen |
|---|---|
| Family | Brassicaceae |
| Mature height | 30–50 cm (12–20 in) |
| Mature spread | 30–60 cm (12–24 in) |
| Spacing | 30 cm (12 in) centre to centre |
| Sun | Shade, at least 1 h of direct sun a day |
| Water | High; drought tolerance none, waterlogging tolerance moderate |
| Soil pH | 6–7 |
| Cold hardiness | About -5 °C (23 °F) once established (roughly USDA zone 9) |
| Heat stress | Likely above about 24 °C (75 °F) |
| Flowering | from about March for 4–7 weeks (northern hemisphere; later in cold climates, earlier in warm ones) |
| Wind tolerance | None |
| Pollinator value | Moderate |
| Edible | Yes: rhizome (grated wasabi), leaves and flowers |
| Native to | Mountain streams of Japan and Sakhalin |
| Common in gardens of | 🇯🇵 Japan, 🇰🇷 South Korea, 🇳🇿 New Zealand, 🇬🇧 United Kingdom |
Is Wasabi toxic?
- People: not known to be toxic
- Cats: not known to be toxic
- Dogs: not known to be toxic
No toxicity reported in ASPCA or standard poison references.
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 Wasabi
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
Questions about Wasabi
- How far apart should I plant Wasabi?
- About 30 cm (12 in) apart, centre to centre. A mature plant spreads 30–60 cm (12–24 in).
- Does Wasabi need full sun?
- Shade: at least 1 hours of direct sun a day.
- How much water does Wasabi need?
- High water. Drought tolerance is none and waterlogging tolerance moderate.
- How cold-hardy is Wasabi?
- It tolerates about -5 °C (23 °F) once established, roughly USDA zone 9.
- When does Wasabi flower?
- From about March for 4–7 weeks (northern hemisphere; later in cold climates, earlier in warm ones).
- Is Wasabi 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. No toxicity reported in ASPCA or standard poison references.
- What grows well with Wasabi?
- 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 B (B: extension service or peer-reviewed).
- Plants of the World Online (taxonomy, native range), Royal Botanic Gardens, Kew
- Plants For A Future database, PFAF
Notes and assumptions
- Famously hard to grow: needs cool (8–20 °C), shaded, constantly moist ground or flowing water. Rhizomes take 18–24 months.
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