One of the oldest hot flavored herbs to be used is horseradish (Armoracia rusticana). The large brown taproot can reach two feet long and 4 inches in diameter. The glossy green leaves grow in clumps and can be almost two feet long. Keep horseradish regularly watered to keep the roots tender and flavorful. To harvest it in fall, simply pull up the plant to get at the central root. Slice off the smaller side roots and replant them for future harvest. Discard any damaged or woody roots older than a year.
Once established, this root herb will be there forever. Digging up the main plant will almost certainly break off lateral roots. It will reproduce from the smallest section of the root left in the soil. One solution is to grow horseradish in a pot where it can be controlled.
Even though it is quite hardy, horseradish does have a few insect enemies. It is susceptible to leaf damage from cabbageworms. This can be controlled with BT insecticide. The roots are sometimes attacked by the white grub-like larvae of crucifer weevil. Treating a weevil infestation requires digging up the roots and treating them with a permethrin solution.
Fresh horseradish sauce is simple to make. Find a well-ventilated location and put on kitchen gloves to protect your skin from the irritating oils. Take 4 ounces of horseradish root and peel it. Using a stainless steel grater, finely grate the root into a glass or ceramic bowl. Immediately add ? tablespoon cider vinegar, 1 teaspoon salt, and 1 tablespoon sugar and stir to combine. Transfer to an airtight container and refrigerate for up to two weeks. If you prefer a milder condiment, try using less raw horseradish and substituting grated apple to make up the volume. To learn more about horseradish visit the Horseradish Information Council online at www.horseradish.org.