You should have no trouble growing a variety of clematis in eastern Tennessee, Jill. Here's a list of cultivars that a nursery in McMinnville carried last season. In my experience, a local nursery that goes to the trouble to put out a list with cultural notes like this one is a nursery that can be trusted. I realize you are substantially east of them, but I doubt your conditions are much different. At any rate, it would give you a starting point for when you visit a nursery closer to you.