Coarse-leaved perennial grown for its pungent roots. Once established, near-impossible to eradicate from a planting.
Hardiness ratings
| System | Rating | Temperature range | How to read it |
|---|---|---|---|
| USDA hardiness zone | Zone 2–9 | −45.6 °C to −1.1 °C | Plant tolerates down to this zone |
| RHS hardiness rating | H7 | down to −20 °C | Plant needs at least this level of cold tolerance |
| Canadian plant hardiness zone | Zone 2–9 | −40 °C and warmer | Plant tolerates down to this zone |
| Australian (ANBG) zone | Zone 1–5 | −15 °C to 10 °C | Plant tolerates down to this zone |
About Horseradish
Horseradish is grown for its root, and like garlic its pungency does not exist until the tissue is damaged: grating or crushing brings an enzyme into contact with compounds that release the sharp, volatile heat, which then fades within minutes unless acid is added. It is closely related to mustard and wasabi, and most product sold as wasabi outside Japan is dyed horseradish. The plant spreads aggressively from the smallest root fragment left in the ground, which makes it very difficult to remove once established and a poor candidate for a mixed bed.
Growing notes
- Any root fragment will regrow — choose your planting site carefully and consider a sunken container
- Lift roots in autumn after the first frosts for the strongest flavour
- Always consult a qualified medical or herbal practitioner before medicinal use.
Pet caution: Horseradish is listed as potentially harmful to cats and/or dogs. Keep pets from grazing on it, and contact a vet if you suspect your animal has eaten some.
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Related plants
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