How far apart should I plant Horseradish?

About 50 cm (20 in) apart, centre to centre. A mature plant spreads 50–80 cm (20–31 in).

Does Horseradish need full sun?

Full sun: at least 5 hours of direct sun a day.

How much water does Horseradish need?

Moderate water. Drought tolerance is moderate and waterlogging tolerance low.

How cold-hardy is Horseradish?

It tolerates about -35 °C (-31 °F) once established, roughly USDA zone 3.

When does Horseradish flower?

From about May for 3–5 weeks (northern hemisphere; later in cold climates, earlier in warm ones).

Is Horseradish poisonous to cats and dogs?

For cats it is mildly toxic; for dogs mildly toxic; for people not known to be toxic. Raw root contains pungent isothiocyanates that irritate the mouth and stomach.

What grows well with Horseradish?

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.

Horseradish Armoracia rusticana

Horseradish (Armoracia rusticana) is a deciduous perennial vegetable in the Brassicaceae family, native to Southeastern Europe and western Asia. It grows 60 cm–1.2 m (24 in–3.9 ft) tall and 50–80 cm (20–31 in) wide, wants full sun and moderate water, and is hardy to about -35 °C (-31 °F). Space plants about 50 cm (20 in) apart.

Plan Horseradish in your garden →
Free. Draw your beds, then watch it grow through the year in 2D and 3D.

Horseradish at a glance

Type	Perennial vegetable, deciduous
Family	Brassicaceae
Mature height	60 cm–1.2 m (24 in–3.9 ft)
Mature spread	50–80 cm (20–31 in)
Spacing	50 cm (20 in) centre to centre
Sun	Full sun, at least 5 h of direct sun a day
Water	Moderate; drought tolerance moderate, waterlogging tolerance low
Soil pH	6–7.5
Cold hardiness	About -35 °C (-31 °F) once established (roughly USDA zone 3)
Heat stress	Likely above about 30 °C (86 °F)
Flowering	from about May for 3–5 weeks (northern hemisphere; later in cold climates, earlier in warm ones)
Wind tolerance	Low
Pollinator value	Moderate
Edible	Yes: roots, young leaves
Native to	Southeastern Europe and western Asia
Common in gardens of	🇩🇪 Germany, 🇷🇺 Russia, 🇺🇸 United States

Is Horseradish toxic?

People: not known to be toxic
Cats: mildly toxic
Dogs: mildly toxic
Parts: roots (raw, large amounts)

Raw root contains pungent isothiocyanates that irritate the mouth and stomach.

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 Horseradish

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 Horseradish

How far apart should I plant Horseradish?: About 50 cm (20 in) apart, centre to centre. A mature plant spreads 50–80 cm (20–31 in).
Does Horseradish need full sun?: Full sun: at least 5 hours of direct sun a day.
How much water does Horseradish need?: Moderate water. Drought tolerance is moderate and waterlogging tolerance low.
How cold-hardy is Horseradish?: It tolerates about -35 °C (-31 °F) once established, roughly USDA zone 3.
When does Horseradish flower?: From about May for 3–5 weeks (northern hemisphere; later in cold climates, earlier in warm ones).
Is Horseradish poisonous to cats and dogs?: For cats it is mildly toxic; for dogs mildly toxic; for people not known to be toxic. Raw root contains pungent isothiocyanates that irritate the mouth and stomach.
What grows well with Horseradish?: 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).

RHS Plant Finder, Royal Horticultural Society
University extension gardening guides (general), Various land-grant university extensions
USDA PLANTS Database, USDA NRCS

Notes and assumptions

Spreads from any root piece left in the soil; best contained in a bed or large pot. Rarely sets seed.

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