Comfrey (Symphytum officinale)

Like: 
1
Edible: 
no
Dynamic Accumulator: 
yes
Perennial: 
yes

contain toxins or carcinogens The most complete chop&drop combination seems to be something like: Coltsfoot + Comfrey + Dandelions + Lamb's Quarters + Vetch

Nutrients: 
K, P, Ca, Cu, Fe, Mg