I live in Zone 9 in New Mexico. I have a lot of roses, a few are climbers. It snows here from time to time. The roses survive. I find that they need some shade protection from the hot sun. White roses, in particular, tend to need shade. If your wall offers partial shade for the roses, they ought to work well.

A friend lives in Paso Robles, California. She planted a hedge of white Simplicity roses last year. She raves about those roses! She said they are very sturdy and bloom constantly. She hasn't mentioned fragrance, so I don't know about that.