Horseradish

Horseradish is a perennial of the cabbage family, grown for its large, white, tapered root, which is used as a spice and a condiment. Wikipedia says it is likely native to south-eastern Europe and western Asia, grows to about a metre and a half, and has hairless bright green leaves and scented white four-petalled flowers. It has been cultivated since antiquity, and the Roman author Pliny the Elder probably mentions it, recommending it for its medicinal qualities. In Europe, horseradish sauce is part of Christian Easter traditions, eaten as a reminder of the bitterness of Jesus' suffering on Good Friday. Cunningham gives it for purification and exorcism: the dried, grated or ground root is sprinkled around the house, in corners, on the outside steps and on doorsills, which makes all evil powers clear out and defuses any spells sent against you. He lists the plant under both Cochlearia armoracia and Armoracia rusticana, the older name.