Astilbes seem resistant to slugs. Carolmc , I have done same thing with hostas this year....pots and copper tape. They have been untouched. For me, the danger from slugs etc occurs when hostas are flowering. If I remove the flowers from hostas in the ground slugs dont seem to be attracted. Mind you, the flowers are nice so...............heathers seem to tolerate slugs, grasses like hackonechloa, uncinia and elymus plus some of the foxy oloured carex also seem untouched. Senecio, agastache and curry plant too