Peony - Leaves are bown
Seems like overnight all leaves turned brown and are brittle. Plants were deadheaded & have remained in the same bed for many years. Do I cut back as usual & hope for the best in the spring?
Lake County Illinois
This is about the time that peonies will start wilting and dying back for the season. With our extreme heat and unusual weather, it's no surprise that your leaves have turned brown. It's not clear, however, from your note whether there is any disease on your plants or if they've simply reached the end of their season. It's also unclear whether you have an herbaceous peony or a tree peony. More information would be helpful to identify the specific problem.
There are several resources to help you identify disease. Here is some basic information about the peony and its pests and problems: http://extension.illinois.edu/hortanswers/PlantDetail.cfm?PlantID=737&PlantTypeID=2
You may find additional information about peonies here:
The Heartland Peony Society also has an interesting website to help you identify the specific species and its care: http://www.peonies.org/index.shtml