http://wohbae.notlong.com Horseradish and Garlic 30 April 2008. Both species are planted in the late fall about October in Zone 5. Horseradish (Armoracia rusticana, syn. Cochlearia armoracia) is a perennial but I treat it as an annual, and propagate the following year's plant from a piece of the current root. It is a member of the Brassicaceae family, which includes mustard, wasabi, and cabbages. I put it in a convenient place for digging in the late Fall, since the roots are a real hassle to remove from the ground, and the plant gets about two feet in diameter and about four feet tall. Hardneck garlic is technically known as the ophioscorodon variety of allium sativum. Hardneck garlics have a "scape" - stalk - which coils from the top. These "scapes" are in much demand, and essentially gives the commercial growers two products from as field of garlic. There are three main types of hardneck garlic: rocambole, porcelain and purple stripe. My type is probably porcelain garlic.