I have never had much results with clematis until this year, and all of that success rests with "Blue Light". Have a few unnamed cultivars that are hanging on but not doing much.
Last summer I saw someone's mailbox with a trellis in back covered with a wall of clematis flowers. It just blew me away.
Late in the season a local nursery had a close-out on clematis plants. I picked up several Blue Lights and they have been just amazing this, their first year. Can't speak highly enough. And their double flowers last much longer than any of the single flowers on my other plants. Highly recommended.