I planted two ninebarks last spring which seemed to be doing ok until they both got what seemed to be powdery mildew and appeared to die back by the fall. I treated the mildew with a fungicide. This year, I had to prune many branches as they seemed dead. I am wondering if fire blight is a possibility as the leaves do shrivel and dry out on the dead branches. I have been spraying to prevent the mildew as I have seen a few leaves infected this year. I'm not having much luck with them, should I be patient and wait to see if they survive or pull them out? Any help would be appreciated!