I’m looking for perennials that do not spread and will bloom in July and/or August. I am on shale.
Some that come to mind are Daisies, coreopsis, daylily, garden phlox, cimcifuga, rudbeckia, coneflower, astilbe, veronica, hosta. yarrow, mallow hibiscus, balloon flowers, gallardia, sedum…there are many. Here’s a link you might find helpful: https://www.thespruce.com/long-blooming-perennials-2131857