Yep good suggestions so far, just what I’d have suggested, plus asters,plumbago,verbena bonariensis- it’s tall but wafts about anyway & nice to ‘see through’. Grasses.peonies of supported. Lily of the valley, Chinese lanterns, poppies all sorts, English marigolds. Eucomis. Day lilies, London pride dwarf sunflowers.
Any shrubs for winter structure?