Horseradish is a perennial (hardy to USDA zone 2) with long roots that can be dug and used for flavoring in fall and winter. You can either leave a few roots in the ground or dig them up and replant them in spring. Native to western Asia originally, it has been cultivated since Roman times and has become so popular that it's now found all over the world.
Getting the Root Started
Dig an area 1 foot deep and 2 feet in diameter, loosening the soil well. Remove half of the dirt, leaving a hole about a foot deep.
Mix 1/2 cup of bone with with the soil remaining in the hole. A slow release fertilizer, bone meal will nourish the growth of the root during the whole season.
Lay your root horizontally across the soil at the bottom of the hole with the larger end-- the one the leaves will sprout from--slightly higher than the smaller end. This makes the root easier to dig in fall than it would be if it were placed vertically.
Cover the root with the remaining soil and water well.
In fall, dig the root and its side shoots up, clean and use in cooking. Any side roots not to be used can be replanted right away or stored in the refrigerator wrapped in plastic for spring planting.