I'm in coastal VA, where it's hotter and sunnier than C-ville, and most varieties of Peony hold their foliage just fine throughout the growing season here, including herbaceous hybrids, tree peonies, and intersectionals. Occasionally one of the species seedlings that I collect (P. japonica and wittmaniana, for instance), will brown off in midsummer, but by and large they look fine until they change to a golden color in fall.

I'd suggest a couple of local field trips to see how the different varieties look in this region throughout the summer. Andre Viette's in Fishersville (about a half hour away from you) has fields and fields of the herbaceous hybrids, and Lewis Ginter Botanical gardens in Richmond has an extensive collection of all types scattered throughout the Asian Valley and perennial garden. You can't really get or plant any bare-root peonies (which is mostly how they're shipped) until fall anyway, so you may as well do some observational visiting this summer. Have fun!