Comfrey Symphytum officinale L.
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.
from wikipedia ( dutch name: smeerwortel)