Comfrey (also comphrey) is an important herb in organic gardening. It is used as a fertilizer and as an herbal medicine. The main species used now is Symphytum × uplandicum or Russian comfrey, a hybrid between Symphytum officinale (common comfrey) and Symphytum asperum (rough comfrey).
Read more about Comfrey: Description, Cultivation, Medicinal Uses