🌱 Horseradish

Horseradish is a tough, fiery root that will thrive for years with almost no care. Its pungent flavour is the classic accompaniment to roast beef, smoked fish and beetroot, and homegrown roots are far stronger than the jarred sauce.

It is so vigorous that it can become a weed: any bit of root left in the ground will regrow, so confine it to a large pot, a bed of its own, or a bottomless bucket sunk into soil.

Varieties to try

Common horseradish (the usual plant)Variegated horseradish (cream-splashed leaves)Bohemian (large, mild roots)Maliner Kren (strong flavour)

Plant root cuttings (called thongs) in February to April, 20–30 cm long and pencil-thick, at a slight angle with the top 5 cm below the surface. Space 45 cm apart in deep, rich, moisture-retentive soil in sun or part shade.

To keep it under control, plant in a bottomless bucket, a tall pot, or a bed edged with deep paving. Cut the top of the thong flat and the bottom at a slant, so you always know which end is up. Water until established.

Top tips

• Plant thongs at an angle.
• Contain it so it can't spread.
• Mark the flat top and slanted bottom.
• Choose deep, moist soil.

Horseradish needs little attention. Water in dry spells, and mulch with compost to keep the roots moist and tender. Remove any flower stalks so that the plant puts its energy into the roots.

Leaves are sometimes holed by flea beetle or caterpillars, which does no harm. White blister fungus can mark the leaves. To improve root size, you can thin the crown to the strongest shoots in early summer.

Top tips

• Mulch in spring.
• Remove flower stems.
• Thin shoots for bigger roots.
• Never let roots escape into the garden.

Watch out for

Flea beetleCaterpillarsWhite blisterSpread by root fragments

Dig roots from October to March, when the foliage has died back and the roots are at their strongest, once the first frosts have sweetened them. Lift with a fork, taking care to get out as much as possible; leave a few thin pieces to regrow, or replant thongs in spring.

Roots from the first year are small; the largest and hottest come from plants in their second year. Rake the soil fully to remove all fragments if you want to clear the bed.

Top tips

• Lift after the first frost.
• Replant thongs for next year.
• Second-year roots are best.
• Clear all root fragments if you move it.

Wash, peel and grate the roots finely, ideally outside or near an open window, since the fumes are powerful. Mix with a little vinegar, cream or crème fraîche to make horseradish sauce, which is superb with roast beef, smoked mackerel, ham and beetroot.

Whole roots keep for several weeks in the fridge, or in damp sand in a cool shed. Grated horseradish in vinegar keeps for a few months in a jar in the fridge, though the heat fades. Freeze grated root in small portions.

Top tips

• Grate outside; the fumes are strong.
• Add vinegar quickly to fix the heat.
• Store roots in damp sand.
• Freeze grated horseradish in portions.