Soft prarie planting: Sedum, Salvias, Origanum, Erigeron and Stipa gigantea and provides year round structure, texture and colour. Photos courtesy of Sarah Price and Rachel Warne.
Mixed fountain grasses plus pee gee hydrangea, white echinacea ("White Swan"), plus possibly some oak leaf or Annabelle, plus possibly low white carpet rose. Maybe add Icicle White Veronica or similar. Do Russian sage and grasses near steps.