You have a powdery mildew problem which is not possible to reverse, only to prevent. Google Peony mildew and read the different options available. Al

Thanks Al. I did google and sounds like too much moisture must be the culprit. I'm going to back-off drip irrigation from every 2nd to every 4th day.

Kevin

calistoga, could there be another reason also? We have had an exremely dry summer, driest on record, and a couple of my peonies have the same problem. At first, when I noticed it, I thought they were extremely dusty because of the lack of rain. I hosed them down thinking I would rinse the 'dust' off of them. Of course that didn't work so I cut them back to almost ground level. I didn't know what to do and I'm wondering if the whole plant is dead or if it will come back in the spring. Will check on Google and see if they can also help. Thanks so much. BT