Prune it now above the second leaf node from the bottom of the stem. After it grows new vines from those nodes pinch the tips after they have a couple of leaf nodes.

Thank you bob414, but I should have been more clear about my clematis. The bottom 2 feet of the plant look completely dead. Part of it is even broken. I still can't believe that it's growing at all based on how the bottom looks. Can I prune it back to the ground to get rid of the dead looking stuff, or do I need to leave some green on it? Thanks!

I hope someone else jumps in with some advice. I would prune it to the ground but I've never had one like you describe. At the very least go on up the stem until you do get above two leaf nodes and prune it there and then pinch the vines that develop from the nodes after they develop a couple of nodes then prune it to the ground early next spring.

I would also prune it to the ground. New sprouts will come up from the buried crown. You did bury the crown when you planted it didn't you?

Hit it with some alfalfa pellets, meal or tea, that should help.

When they grow one long scraggly vine they usually will not ever "bush out" unless hard pruned.

Jackmanii is one that should be hard pruned every year.