You might want to check out the Clematis forum they have lotsa ideas and suggestions...Although owner of 2 (this being the 2nd yr) haven't had enough experience to know...
juanital

I had several Clematis when I lived in Michigan. What I couldn't figure out was why some would flourish and some would start to grow and then die off. I believed it had to do with how much light they were getting. You may want to keep that in mind. I do know that the base of the plant doesn't like direct heat from what I read. I always covered them with wood chips. They are beautiful and I really enjoyed having them. I am planning to plant one at my new house here in NC this year too.

You may want to view different opinions on prunning when they die off too. I used to cut all the dead vine off but I would wait until it started blooming in the spring because Clematis stars re-growing on itself at random places. I had friends tell me they would chop it off at the base and let it start from the ground up. Mine were always full of blooms and really thick and hardy.