This is a native Texas clematis, commonly called "Leathercup vine." The flowers are tough, like leather. It's also called Pitcher Clematis. It's botanical name is clematis pitcherii. "Cup" of Leathercup vine ( photo / image / picture from marlingardener's Garden ) We have the vine growing on the support by our front door where the little flowers show up. Surprisingly, hummingbirds like it. The seed pods are very interesting (weird?) and people use them in dried flower arrangements. Leathercup vine (clematis) ( photo / image / picture from marlingardener's Garden )
I've never seen this clematis before but I think I like it. So glad the hummingbirds enjoy it flowering in your garden.