Peony Fungus ?
Peony leaf spots are often managed through sanitation. The fungus survives the winter in infected plant debris. Diseased plant material should be removed in fall. Cut off the stems at ground level. Remove the plant debris from the area and destroy it. Proper spacing and watering can help to minimize the severity of the disease. Space peonies three to four feet apart and when watering is necessary, avoid wetting the peony foliage. Fungicides can be used as a supplement to sanitation and good cultural practices. Fungicides prevent disease but do not cure an infected leaf once it is infected.