Powdery mildew on peonies

Question

Is mid July to late to spray. Most of the leaves are half covered already. I tried earlier in early June with no results.
Also, what should I do this fall when I cut them back.
Thanks

Answer 1

You can treat the plants every 10 to 14 days through the summer months.

https://www.gardeningknowhow.com/ornamental/flowers/peony/powdery-mildew-peonies.htm