I have a pole with a birdfeeder hanging from it in my yard. It happens to be in a flower bed that doesn't receive as much water as the rest of the yard. I would really like to grow a clematis on the pole in this location. Most of the time I can remember to give it an extra bit of water by hand, but there are times when I get busy and forget. July here can reach a scorching 116 F here. Is there a large flowered clematis that will tolerate some drought on my forgetful days?

Monica