I fear that my endless summer may have been overrun by powdery mildew. At first, I thought the leaves were browning and becoming crisp because I had removed a tree from the bed that had become overgrown--but this tree had provided the hydrangea with dappled afternoon shade, so I thought the rapid increase in sun was to blame. Now, since I can see everything clearly in the sun, I see white powdery spots and leaves going purple and getting crisp. Should I do anything, or let it be? I have heard that powdery mildew will not kill, but this plant was put in this Spring, so I am not sure it can withstand it. Any advice is appreciated, thank you.