Horseradish

Photo: Pethan — CC BY-SA 3.0 · source

Survives zone 3 through 9

Harvest calendar

Ripens: Root harvested in late autumn after the first frost, for the sharpest flavor

Best planted in early spring after your last frost, or in fall before the ground freezes, depending on your climate.

Grated fresh root is intensely pungent — the sharp, sinus-clearing heat comes from the same class of compounds (glucosinolates) as mustard and wasabi, and fades quickly once cut or ground, so it's prepared close to serving. Extremely persistent once planted: even a small piece of root left in the ground will regrow.

Hardiness

Zone 3–9

Habit

Herb

Edible part

Root

Ripens

Root harvested in late autumn after the first frost, for the sharpest flavor

Mature size

Perennial to about 0.6–1 m; roots can run deep and wide

Light

Full sun to part shade

Soil pH

6.0–7.5

Environment

Temperate

Native range

Southeastern Europe and western Asia, naturalized widely across temperate regions.

Status

Both wild and cultivated

Years to fruit

1 yr

Growth speed

Fast — a set makes a harvestable root in a single season

Spacing

45 cm (18 in) apart — about 4.9 per m² (4.6 per 10 sq ft)

Leaf shape

Very large basal leaves 30–100 cm, oblong, coarsely toothed and wavy-edged, on long stalks — young leaves are edible and mustard-hot, and worth knowing about since the plant makes far more leaf than root.

Root system

Long, deep taproot with vigorous lateral roots — hard to fully remove once established.

Fruit description

Not a fruit crop. Most cultivated horseradish is effectively sterile and sets no viable seed at all; where a plant does flower, the white sprays give small pods that come to nothing. The crop is the root.

Propagation

Root cuttings ("sets") planted in early spring, using side-root pieces from a harvested plant.

Pollination

Largely sterile in cultivation — the widely grown clones set little or no viable seed, and the plant is propagated only from root pieces. Pollination has no bearing on the crop.

The edible parts listed above are a starting point, not a field guide. Identify a plant with certainty — ideally against a local authority — before eating any part of it, and read the full disclaimer. Spotted something wrong? Report it.