Posted: 20/08/2013 at 17:11
Thanks for the reassuring comments. When I looked at them yesterday I realised that it is the ones which are in an open, sunny bed which have virtually no flowers. I had conscientiously fed and watered them to make up for the lack of rain - but, as you say, it could be the heat. I think I'll leave them where they are, because they were brilliant last year.
Thanks again for your interest.