Although horseradish (Armoracia rusticana) is a perennial it is best grown as an annual. The leaves are long, dull green ovals with jagged edges and the root is long and tough. Since horseradish is not a very attractive plant it may be best grown tucked away at the back of the garden.
Horseradish grows in well-drained soil that has been dug over deeply with plenty of rotted manure in a position with full or part sun.
New plants can be grown using pieces of the root purchased from the green grocer towards the end of winter. Almost any small piece will take which can make it difficult to eradicate once it is in the garden. For sure success, use a piece about 15 cm long and plant almost horizontally 5 cm below the surface. Keep the ground moist and fertilise occasionally with a low nitrogen liquid fertiliser. Too much nitrogen will produce excessive leaves and poor quality roots. The leaves of horseradish are particularly attractive to snails and slugs so it may be best to lay some snail pellets as well.
The main harvest for horseradish is autumn. Use the main taproot for processing and save the side shoots for replanting. Fresh whole roots will last about two weeks in the fridge or can be frozen in foil for up to 6 months.