Horseradish
Armoracia rusticana
Horseradish is a vigorous perennial grown for its thick, white roots, grated to make a fiery condiment. It is very easy but spreads persistently, so it is best grown in a deep container.
Photo: Pethan · CC BY-SA 3.0, via Wikimedia Commons
Essential Care Requirements
Light
Full sun, Partial sun
Watering
Moderate
Water in dry spells.
Soil
Deep, moist, fertile soil; pH 6.0–7.5.
Temperature and humidity
-30–30 °C · Moderate humidity
Feeding
Light feeding in spring.
Pruning and propagation
Propagate by division
Remove flower stalks.
Safe in condiment amounts. The pungent compounds irritate the eyes, mouth and stomach and can upset pets.
Top Cultivation Tips
Grow in a deep tub to control spreading.
Any piece of root left behind will regrow.
Grate in a well-ventilated room.
Roots are most pungent after frost.
Common problems
Caterpillars
The larvae of moths and butterflies, which chew holes in leaves, flowers and fruit and can strip a plant in days.
How to treat it →DiseaseLeaf spot
Fungal or bacterial infections that cause brown, black or purple spots on leaves, often with a yellow halo, leading to early leaf drop.
How to treat it →DiseaseWhite rust
A disease that forms white, chalky blisters on the undersides of leaves of mustard greens, amaranth, radish and other leafy crops.
How to treat it →
