I'm re-landscaping my back yard and I have a 20 ft across garage wall that I will raise 5- 4x8' redwood lattice (in frames) as a support for a climbing vine to spread out and show some color. I'm new to gardening and not familair with the pros and cons of clematis - I just know how beautiful the blooms always look in photos, so I want to put it on my list (also considering trumpet vine). Any ideas as to how clematis would work here. The wall gets full sun from mid-morning on and I can sprinkler the roots (or not) I am building a deck just nearby, so I want to keep the climber on the trellis and the garage wall - not into constant pruning but willing to do some to keep it under control. Drainage is fair as the yard slopes slightly toward the foundation of the garage wall. I do have an issue with rats, so I plan to mount the lattice frames a few inches off the wall - don't want anything too thick and dense (like bougenvilla for the critters to enjoy!) Not sure how many plants I would need to cover 20 feet at maturity, but I would like a fairly rapid grower...

Thanks!