How do you treat mildew/fungus on peiones ?

Causes And Treatments For Powdery Mildew On Peonies

1. https://www.gardeningknowhow.com › Ornamental Gardens › Flowers › Peonies
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Mar 15, 2015 - It's likely due to powdery mildew. Powdery mildew can affect many plants, including peonies. Although this fungal disease doesn't usually kill ...

Powdery Mildew on Peonies - Mike's Backyard Nursery

1. mikesbackyardnursery.com/2014/08/powdery-mildew-on-peonies/
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Aug 21, 2014 - Peonies with powdery mildew. Powdery mildew is one of the most commonly found fungal problems affecting plants. This fungus typically ...

fungus - What do I do about the whitish powdery mold on my peonies ...

1. https://gardening.stackexchange.com/.../what-do-i-do-about-the-whitish-powdery-mol...

This may help

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

I just read an article on powdery mildew that says milk will work. Whole milk or 60/40 milk and water. The problem with powdery mildew is we usually don't notice it until it is on the leaves. It kills the vines and stems of many plants and then we notice it on the leaves. Spray AS SOON AS you notice, getting vines and stems and retreat after rain. It has been a horrible problem from peonies, lilacs to cukes, pumpkins, and any squash this year.

I use bar soap to make a froth like you used to use for shaving face. I use an old soft paint brush to apply liberally to the buds and leaves. Side benefit is fertilizing effect and no sticky thrips.

Peonies are very susceptible to fungus. Just cut them back now they are done for the season. If it really bothers you, next spring start treat the plants as they emerge from the ground with a fungicide. Good luck!