I had a similar experience.... although some say not, I am sure it was "clematis wilt". It was the second year for mine and it grew fast, and then just kept wilting. I finally pulled it out! Apparently, there is no cure and it is not contagious, so if you do have wilt, you can safely plant another one in the same place. Good luck!

You know, some of my newly planted started doing the same thing. Unfortunately I don't know what kind she is. Unabeled, I bought it for the surprise. The tips and little buds just turn black, and bend some bud bend 180 degrees, hanging dead. I suspect it's insect damage, because I see some black frilled damage on other young leaves before they start wilting.
I sure hope that Wesgate is mistaken, I would cry to have to pull mine out, I just bought her a trelis too. I"ve read about clematis coming back from the dead as late as two years after the fact, so I would not dig anything out, just plant something else nearby if it becomes an eyesore spot. and yes, I throw away the wilted pieces, I trim them somewhere underneath the damage, if I can.
I hope somebody with more experience will come along and answer your question.