Limousin, France

I have a garden in France with a much beloved clematis (ville de Lyon, I've with GOY kind members identified it). It shows as flourisihing in the estate agents' June blurb photos when I bought the house so is at least eight years old and more. This year it is flowering fantastically as usual but it has white patches along the stems and blotches on the leaves. Any advice? (we like you have had lots of rain recently - after an early drought which I don't think you experienced!) Thanks, all...

• 3 May, 2014