Maybe you have 'Recta' which looks like Sweet Autumn but blooms now. Recta is a non-clinging vine though. I help mine twine through the trellis.

Or Clematis vitalba, which looks exactly like SAC except for leaf form and an earlier bloom season. Also considered an invasive species/noxious weed throughout much of the US.

I was told by the nursery that this is a hybrid of some sort and they are returning them to vendor. So I guess it's a Summer Fake Clematis. Thanks all!