My hydrangeas and other shrubs have got something that has turned their leaves brown and it looks like they are dying. We have had a hot summer preceded by a ton of rain so I'm assuming it is a fungal disease. I have sprayed several times but it still looks bad. My question is should I just leave them be until next spring when I'll start over or will it kill them and what should I put on them because what I've been using doesn't seem to be helping. I've used a copper powder.