I read your reply to “white powder on peonies”.
To treat a similar mildew, I took the option of snipping leaves instead of using a chemical. However, by the time i was finished, most of the foliage was gone. Then I remember reading a previous suggestion which stated that the foliage wasn’t supposed to be removed until Fall. I noticed that the roses are responding to composting and watering, so maybe I panicked, not wishing to see the disease spread. Hindsight made me realize the disease has been there for years, and it hasn’t spread to the roses.
These plants have lots of sun, and space. However, I noticed that the soaker hose runs through the middle of one group of stems, meaning peonies get wet feet. I’ve applied compost (Promix sheep manure), but perhaps too late in the season. I haven’t used fertilizer.
I have a second Peonie group with a similar condition which I haven’t cut away. I could try to use a chemical with that one.
What is a risk to removing most of the foliage to the first plant? Can I do anything that could protect the plant, such as wrap it in something, such as the winter bushes I see protected?
As noted in the TMG gardener reply which you have already reviewed, the powdery mildew infecting your peonies should not cause permanent damage to your plants, although it can be unsightly and disfiguring during a particular growing season.
While it advisable to wait until fall to remove the infected leaves, removing them early should not prove fatal, although removing the leaves means that the plants will not have as much green growth to photosynthesize and use to create/store nutrients for the winter.
As noted in the previous response next year you can consider applying preventative fungicide.