I too am sorry about this terrible event. I also agree with others about removing the foliage before flushing the soil with water. I am already pruning my peonies as some are more affected by blackspot and powdery mildew earlier than others. I have not seen tremendous effect on blooming of pruning early done to these peonies. They continue to bloom for me year after year. Good luck and I hope your peonies will make it through this exposure.
