Spots on peony
Peonies are susceptible to a fungal infection known as Peony Leaf Spot. The references above will tell you more. At the end of the growing season, remove and destroy all of the stems and foliage to remove the fungal spores from your landscape. Some varieties are more susceptible to this infection than others. The plant will usually survive the infection but sanitation will reduce the amount of inoculum available for next year.