Peony Red Blotch

Sherrie Smith and Jason Pavel

Plant Health Clinic Disease Note Issue 12

Peony Red Blotch-Graphiopsis chlorocephala, formerly Cladosporium paeoniae. (Photo by Sherrie Smith, University of Arkansas System Cooperative Extension Service)

Peonies are up and have buds. They are one of our finest perennials. They are exceptionally long-lived, reaching ages of 50 years or more. They are also very healthy when planted with a minimum of 6 hours of sun in good garden soil with excellent drainage.

Perhaps the most common disease we find on peonies is Red Spot (Blotch), caused by Peony leaf blotch, Graphiopsis chlorocephala, formerly Cladosporium paeoniae.

This looks ugly but does not significantly damage the plant. Symptoms begin as small, circular, red to purple spots on the upper surface of young leaves. These spots become a burnished dark purple. The undersides of the leaves become a chestnut brown color. Later in the season, the lesions coalesce, becoming large, irregular purple blotches.

Susceptibility to Red spot is quite variable, with many older cultivars being the most susceptible. It is important to clean up peony debris. In the fall, prune all spent top growth to ground level, and remove it from the garden. Begin spraying on a weekly schedule when new growth is just breaking the soil in the spring, continuing until the flowers begin to open. Fungicides containing chlorothalonil, thiophanate-methyl, or copper are effective.

Take Aways:

• Practice good sanitation.
• Apply fungicides at new growth in the spring.

Peony Red Blotch-Graphiopsis chlorocephala, formerly Cladosporium paeoniae. (Photo by Sherrie Smith, University of Arkansas System Cooperative Extension Service)

This work is supported by the Crop Protection and Pest Management Program [grant no. 2017-70006- 27279/project accession no. 1013890] from the USDA National Institute of Food and Agriculture.

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