My Peony Leaves Are Dead After Powdery Mildew.

Question

I sprayed for powdery mildew a couple of times early in the summer with a homemade solution, then something I got at a Hardware store. Neither seemed to do any good. I researched and thought mulch was the thing to add to keep the mildew out of the dirt so I spread mulch early July. Should I cut these to the ground now? Should I replace the mulch?

Answer 1

Yes, you can cut back the foliage. The fungicides typically don't help if the plant already has powdery mildew. Fungicides work better as a preventative than as a solution to fungal infections. The best thing to do is to make sure your peony is in full sun or at least mostly sun. Powdery mildew creeps up when a plant is too shaded. Also, be sure to pick up any fallen leaves so you can reduce the incidence next spring. You don't need to replace the mulch, but be sure you get all the fallen leaves.

Here is more:

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