I have some relaly pretty waffle
plants-their leaves are crinkly-a gorgeous deep green on top and purple underneath. They have small white
flowers that shoot up.
PURPLE
flowers:
Delphiniums bloom summer-autumn, You could use Lobelia as edging-teeny little purple blossoms,
Irises of course, grape hyacinth, Morning glories, wisteria, asters, my dad's hostas have lavender blossoms coming up out of the center- they look really nice, balloon
flowers, Toad lilies, all kinds of lavender-many have silvery foliage, different types of sage have purple blossoms- and tricolor sage has purpley silver foliage also. Purple & white blooming butterfly bushes
Lamb's ears are nice and silvery. Chinese bush Cherry just looks cool....Sorry....I'm rambling
Hope I was of some help- I know a lot of these are sort of basic-at least where I live.