Clematis: Need advice with vines/climbers, 0 by Wizzie

Wizzie wrote:
Hello everyone!

This is my first post here, and I figured this would be a good place to start, since this problem has been bothering me for the last few years. I've tried growing clematis (it wasn't correctly labled and I planted in the wrong spot) and specifically trumpet vine on this west facing wall of the building in the image. We live in the highlands of northeastern washington by the canadian border, which is around zone 5. We usually have cold winters, the lowest temperature we've had is -25. In the summer the average temperature is around 85 but it can get to around 101 in august/september, with low humidity.

Now, the problem is that I planted these guys three years ago and they don't grow very much during the summer, maybe three to seven inches during august (late). Then during the winter whatever new growth there was dies off. I fertilize them two times during the summer and mulch them. I've also kept them well watered on a timer system. I can understand why the clematis doesn't grow very well in these conditions (hot afternoon sun on a metal wall), but I don't understand why the trumpet vine won't grow. I have a friend who did a similar thing with trumpet vine around the time I planted mine and it's all over her wall now. What I want to do is cover this wall with SOME kind of climber/vine(s), I'm not very particular as to what it is as long as it grows well in these conditions. Water is no issue! Any reccomendations? And thanks for your time.
Karl