Is it just the blooms that are wilting? The leaves look really healthy from your photo. Could the blooms just be old?
the blooms are not old and I pulled out a lot of dead twigs, I've had this plant for about 10 yrs and this never happened before.
Could be Clematis wilt. I have noticed sometimes it starts with the buds drooping, altho i have never seen the blooms themselves droop.
This post was edited by maet on Fri, Jul 18, 14 at 13:32
I'd suspect some sort of damage to the stems......maybe as you were removing dead twigs? Also, animals(pest as well as other critters) can easily break or damage stems as well.
It would be extremely unusual for this to be clematis wilt in a 10 year old plant that had never experienced it before. That is more typically an ailment of young vines which then eventually grow out of it......not the other way around.
I've some very small baby bunnies nip a couple of mine off or just break the stem a bit very low which of course causes wilt. Check for nips or breakage very near the ground. Luckily, (I think and hope!) the bunnies have grown a bit and moved out of the yard to the other side of the chain link fence! We have a border collie, but she only looks for and chases squirrels. Rabbits she doesn't give the time of day to. We used to have a husky who just LOVED the rabbits and kept the population very low and very afraid when they entered the yard.