What is wrong with my peony leaves?


What is wrong with my peony leaves?


Foliar diseases like leaf blotch and powdery mildew can discolor or spot peony leaves.  Peony leaf blotch (Cladosporium) causes irregular brownish-purple spots on peony leaves in summer.  The powdery mildew fungus (Erysiphe) covers the leaves in what looks like a dusting of white powder.  See photo below.  Once these diseases appear on the leaves, there is little that a gardener can do.  Fortunately, both types of foliar diseases do not typically kill peony plants.  In the fall remove the diseased leaves and discard them to prevent re-infection next year.  Diseased leaves should not be composted. 
Another consideration may be the location of the peonies.  Peonies planted in too much shade frequently have more problems with foliar diseases than peonies in full sun.  

Learn more about growing peonies in Iowa in this article: Growing Peonies in Iowa

Dusty peony leaves that are infested with powdery mildew
Powdery mildew fungus covers the leaves in a dusting of white powder.

Links to this article are strongly encouraged, and this article may be republished without further permission if published as written and if credit is given to the author, Horticulture and Home Pest News, and Iowa State University Extension and Outreach. If this article is to be used in any other manner, permission from the author is required. This article was originally published on . The information contained within may not be the most current and accurate depending on when it is accessed.