By Bernard
Cambridgeshire,
United Kingdom 
Clematis problem.
Up till now, this clematis (Haku Ookan) has been growing well, putting on reasonably good quality growth with the young flower buds lookig healthy and maturing nicely. However, once they reach the flowering stage the buds deteriorate and the petals are deformed as the photograph shows. I am completely baffled by this and I hope someone will be a able to shine a light on the mystery.
On plant
Cllematis 'Haku Ookan'
2 Jun, 2010
Answers
Thanks for your advice Sbg. I have broken open a bud and there are no signs of any maggots. It looks as though all the buds are similarly affected so its a problem for the whole plant rather than one bud. I've sprayed it with Roseclear and I wonder if it would be a good idea to cut off all the buds that are deteriorating. Have you any further thoughts?
3 Jun, 2010
it could be a viral thing which wont have a cure. Roseclear will sort out any fungal problems so fingers crossed. Glad it wasnt a gall midge type thing.
I wonder if they got damaged by the frosts we had 3 weeks ago? grasping at straws really.
4 Jun, 2010
Previous question
this looks like typical thrip or aphid damage. It could also be caused by a midge.[similar to hemoracallis gall midge] try breaking open a deformed bud an see ifyou can see any tiny maggots inside the flower.
I think I would spray it wih a systemmic insecticide just in case. but do it in the evening when most of the bees are safe in the hives.
2 Jun, 2010