Comfrey Plants Roots For Sale. Comfrey plants and roots for sale. Comfrey are an important perennial herb in organic gardening. * Most important Comfrey make all the nutrients and micronutrients any plant would need. Seep the Comfrey leaves in a bucket of water and watch what happens. Comfrey has a black, turnip-like root and large hairy broad leaves that bear small bell-shaped flowers of various colors, typically cream or purple. Comfrey is a fast growing plant, producing huge amounts of leaf during the growing season, and hence is very nitrogen hungry. * Buy many and enjoy the benefits of gardening Comfrey.