I've had record rainfall this year and hope this is the cause of leaf spots. What else might it be?

This usually happens to my peonies in August. It is probably too early for this to be happening to your peony if you are located in my zone. Though if you are in a warmer zone, it is probably normal Hopefully you have good drainage where your peony is planted and the yellowing is not due to rot. Best thing that you can do now is cut off the peony foliage, clear the weeds so that the plant has better air circulation, and mulch to keep the roots cool.

Mine do that every year it seems ,not sure what it is though.never gave it a thought since they always came back every year.

I learned long ago to never water the foliage on peonies. They will spot and burn much as the one pictured. Rain water does not cause them to spot but tap water will. It may be the chlorine in the water. I use a leaky bucket to water under the foliage.

Never watered mine,we have had a ton of rain though.

Peony Blotch
http://www.missouribotanicalga...

Some time ago, we discussed 'Roselette'. My plant always becomes covered with a gray dusty material. Doesn't appear to be a problem since it does very well each year.





I finally remembered the common name for the gray substance. I think it is powdery mildew or something like that.

We have had record rainfall in Michigan this year. I have many peonies with mildew. More than normal.