Help with peonies

Asked October 23, 2017, 3:13 PM EDT

What's happening with my peonies? Can they be saved? I have 4 different varieties of peony in my gardens (not sure what kind--they were here when I bought the house). Last year, the plants all turned black & looked burnt. Hoping that it was a fungus, I carefully cut them back last fall, and cleared back the mulch the previous owners had put up to & over the crowns. This spring, I again carefully cleaned the garden beds, making sure that any tree leaves from the previous fall/winter were gone, and the crowns were clear. I had lovely blooms, and the plants looked pretty healthy for most of the summer, until maybe late August, when they started to turn sort of tan & brown. Now, with the weather changing, I've been cutting them back to prepare for winter, and realized that there's some kind of fuzzy mold on the stalks, and the center of most of the crowns looks like it's rotting. (Pictures attached, showing the discolored foliage, fuzz on the stalks, and rotted-looking rhizome.) I thought to dig up the plants and cut away the rotten pieces, and replant only healthy rhizomes with eyes. But I'm not sure I can find any good pieces of rhizome that have eyes... Do you think they can be saved? Or should I just scrap the whole lot and start over? (I probably have about 9 good-sized peonies. They all seem to be affected, though some are worse than others.)

Hennepin County Minnesota peonies

1 Response

I can't tell from a photo if it is powdery mildew or white mold. I think it is powdery mildew and the usual treatment is to cut all the leaves and stems off and they should be fine next year. The mildew is unsightly but does not do serious harm to the peony.
Here is a fact sheet on the more serious peony diseases.
https://www.extension.umn.edu/garden/yard-garden/flowers/diseases-of-peony/