Perennial.
Comfrey (Symphytum officinale L.) is a perennial herb of the family Boraginaceae with a black, turnip-like root and large, hairy broad leaves that bears small bell-shaped white, cream, purple or pink flowers. It is native to Europe, growing in damp, grassy places, and is widespread throughout the British Isles on river banks and ditches. Comfrey has long been recognised by both organic gardeners and herbalists for its great usefulness and versatility.
The comfrey bed should be well prepared by weeding thoroughly, and dressing with manure if available. Offsets should be planted 2-3 feet apart with the growing points just below the surface, whilst root segments should be buried about 2 inches deep. Keep the bed well watered until the young plants are established. Comfrey should not be harvested in its first season as it needs to become established. Any flowering stems should be removed as these will weaken the plants in its first year. Comfrey should also be regularly watered until well established.