How to grow horseradish plant
Advice on growing and caring for horseradish plant, in our guide.
Horseradish plant (Armoracia rusticana) is a large, vigorous and hardy edible perennial, principally grown for its root although its young leaves are also edible. Horseradish is thought to have originated in south-eastern Europe and western Asia before spreading widely and naturalising throughout Europe and Britain – it's often found growing wild along hedgerows and field edges. For many hundreds of years, horseradish has been used for both edible and medicinal purposes. In the UK, a sauce made from horseradish root is popularly used as an accompaniment to roast beef, although the grated root also suits being used in dips, dressings, mixed with mayonnaise, and in coleslaw.
Identifying horseradish plant
Horseradish plant forms dense clumps of huge leaves which can be up to 60cm long. The leaves are a deep rich green in colour with wavy edges. Stems of small white flowers are sometimes borne in early to mid-summer. The leaves of horseradish die back in autumn and regrow in spring.
Horseradish can be confused with dock, which also has large leaves. However, horseradish leaves are larger than dock leaves, and are shiny, while dock leaves are matted. In winter, horseradish root may be confused with monkshood root, which is extremely toxic and should not be eaten. To avoid any confusion, harvest horseradish only when you have seen its leaves, either by harvesting earlier in the season or if you have planted it yourself.
How to grow horseradish plant
Grow horseradish in any reasonable soil in sun or partial shade. Cut back faded leaves in autumn. After a year or two you can harvest sections of root using a sharp spade. Propagate by division or root cuttings.
Where to plant horseradish
Horseradish plant is available as bare-rooted 'thongs' in late winter or early spring. Pot grown plants aren’t widely available but can be planted at any time of year. Horseradish thrives in a wide range of sites and soils, but does best in full sun to partial shade in free-draining soil that is rich in organic matter. Choose the site with care as horseradish plants are almost impossible to get rid once established. Alternatively, grow horseradish in a large and container such as a wooden half barrel. Don't plant horseradish where livestock graze as the leaves are toxic if consumed in quantity.
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How to plant horseradish
Prepare the ground by digging deeply. If planting a bare-root thong, plant it vertically with the tip around 10cm below the soil surface, spacing more than one plant 60-90cm apart. Firm the soil to ensure good contact with the root. If planting a container-grown plant, plant it at the same depth it was in the pot. Water thoroughly, then keep well watered during dry spells until established. If growing in a large container, use a soil-based potting compost.
How to care for horseradish
Very little care is needed once horseradish plant is established in the ground, apart from cutting back the leaves once dead, in autumn.
When growing horseradish plant in containers, water regularly and feed monthly during the growing season with a liquid fertiliser.
How to propagate horseradish
Most home growers need only one clump of horseradish, but you can make new plants by taking 15cm sections of root and planting them in a container of soil-based compost. Keep watered until you see signs of growth.
How to harvest horseradish
Dig up pieces of root as required, taking a portion using a sharp spade, although it may be possible to pull up sections of root if the soil is light and sandy. The roots are at their most spicy and flavoursome when harvested in October or November.
Bear in mind that it's advisable to wear gloves when harvesting, handling and preparing horseradish, as contact with any part of the plant may irritate your skin. The strong fumes given off by horseradish root when peeling and grating can irritate the eyes and it's best done outdoors, or in a well-ventilated room.
It's also worth noting that, once peeled, horseradish root discolours quickly unless placed in a solution of water and white vinegar, so it's best used in recipes straight away.
Pests and diseases
Horseradish plant is a vigorous grower and is usually free of pests and diseases. The caterpillars of the large and small white butterflies (also known as 'cabbage whites') may feed on the leaves although this rarely affects the vigour of this plant. Young plants may need protection from slugs and snails until established. Aphids may be found on horseradish, though are rarely an issue on established plants and are best controlled by encouraging natural, beneficial predators such as ladybirds and house sparrows.
Advice on buying horseradish root
- Buy horseradish as bare roots of 'thongs', which are despatched in late winter
- Horseradish plants are sometimes sold growing in pots, but bare roots give plants the best start in life as pots do not give a great deal of growing room for this deep-rooted plant
Where to buy horseradish thongs
Frequently asked questions
Can you eat the leaves of a horseradish plant?
Young leaves of horseradish are edible when very young in spring, though quickly develop a bitter flavour. Use in salads or cook and serve as a green vegetable.
Can you forage for wild horseradish plant?
Horseradish plant has spread and naturalised into the wild and may be found on roadsides and waste ground. Ideally identify wild horseradish plant while in growth to avoid confusion. The pungent smell of the cut, exposed root is a clear indication of the correct plant.
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