What is causing yellow spots on the leaves of my peonies?
My peonies have yellow spots on the leaves, which can be rubbed off. Every single one of the 50 new plants that I planted in the fall have the same spots on the leaves. Also, some, not all, of the leaves are starting to curl up. I don't see this particular problem on any site that I've looked on.
It is very difficult to diagnose without seeing the plant or close-up photos. There are several pests and diseases that affect peonies aside from the usual aphids, etc. (Click on this link to find some of these: A Visual Guide: Peony Problems.)
I suggest you take a sample (sealed in a plastic bag) to your local Cooperative Extension office at http://www.ccebroomecounty.com/Programs/horticulture, local Master Gardeners, or the vendor from which you obtained the plants.