Being a UK based forum, it's difficult to know what's available in the states and what weather you get.

When you say "Perennials", do you mean shrubs or herbaceous (plants which die down to the ground every winter then come up again in spring)

There's lots to choose from...some long flowering herbaceous perennials are...Heleniums, Leucanthemums, Rudbeckia, Penstemons, Coreopsis, Gailardia, hardy Salvia, Echinacea, Phlox, Solidago,

Not forgetting hardy Geraniums!

then there are the ornamental grasses too.