These include bacterial blight, foliage becoming coated with a fungal powdery mildew, or root rot that entirely stunts growth due to a lack of oxygen (often as a result of overwatering). However, you ...

The most common plant diseases, like powdery mildew or botrytis, a fungal rot, appear on peony foliage and stems. Remove infected areas or treat the plant with a fungal spray. Peonies are not ...