![Many of the leaf spot diseases that are apparent on hydrangeas in the fall are actually the result of infections that occurred in the spring. Cercospora leaf spot, pictured here, is a common disease on bigleaf hydrangeas.](https://secure.caes.uga.edu/news/multimedia/images/5856/Cercospora-leaf-spot-Hydrangea-web.jpg)
Seeing Spots
With all of the rain that we’ve experienced this year, many fungal leaf spot diseases are active. Hydrangeas are particularly susceptible to several different leaf spot diseases that favor moist weather. Some of the most common diseases people ask about are known as Corynespora leaf spot and Cercospora leaf spot on bigleaf hydrangeas.