Comfrey
All comfrey species have hairy leaves and these, as well as the roots, can cause irritation to the skin and should not be eaten. They are however excellent groundcover plants both in a shady border or in a woodland garden where they will happily become rampant in a darker corner where little else will want to grow.
S. grandiflorum ‘Wisley Blue’ is, at first, erect growing but then flops over. It is a rhizomatous perennial with ovate or elliptic lance shaped leaves of up to 8-10in in length. The strong blue flowers are produced in April and on into summer in cymes from red tipped buds. The plant grows to an overall height of about 15in.
The roots are fleshy so root cuttings overwintered in the greenhouse are straightforward but it is probably easier just to divide up a clump in early spring to generate more plants.