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.
Annabelle hydrangea in a formal garden. Behind the hydrangea is a pleached hedge and beneath it a small, tightly clipped box hedge -- here, with a paver stone, but could be equally lovely with lawn or pebbles