Armoracia rusticana. Horseradish ships as a root segment. Plant this in the spring, after danger of frost has passed, and it grows into a rosette of wide, strap-like leaves. In summer it sends up a flower spike that can grow to four feet tall. Horseradish growers dig up the complete root system at the end of summer, reserving some segments of it for re-planting the following spring. These can be kept fresh like dahlia tubers, by storing them in a frost-free environment in paper bags or sawdust.
The root itself can be grated to add its distinctive, spicy flavour to a range of sauces. It pairs well with meat dishes. Horseradish is a perennial plant that was native to southeastern Europe. It is hardy to Zone 2.