Is this from over watering? I can't think of what else I might be doing wrong. The conditions are that we're in Florida, it's extremely hot, this hydrangea was just planted last spring, we've been getting a ton of rain. It's only happening on one side of the plant- the side that does not face the house, which is the south side. Not sure if that info means anything. Otherwise, it's taken very well and I haven't had any problems.