Astilbe flowers drooping

I have two well established Astilbes of different varieties living in a shady part of my garden, which is probably the dampest area as well. The smaller one has a few flowers this year but they're all standing upright. The bigger of the two plants has some lovely deep pink flowers but all of them seem to have taken on a fuschia flower habit - they hang rather than stand to attention! We had a whole day of rain on Saturday so it's unlikely to be lack of water and I even tested the moisture level of the soil with a 'gadget' this morning and all looked fine. I really like the flowers however they perform and it could be just the weight of the flowers that the stem is unable to support but thought I'd ask out of curiosity.....any ideas please?