I recently purchased a home in Highland Park. The backyard has 3 large areas of peony plants, each area located 20 feet apart. Pictures online look to me like all of the plants have developed phytophthora blight. One of the areas has turned brown and has died. The other 2 areas look like they're on the way to dying, too. Please advise me on what to do next. Thank you. Rebecca Pearson
Ramsey County Minnesota
It can be difficult to distinguish phytophthora blight from botrytis. Because many experts recommend removing plants affected by phytophthora, it's important to know which is present. If many plants are involved, we recommend taking or sending samples to the University of Minnesota Plant Disease Clinic for a certain diagnosis.
Otherwise, follow the recommendations published in this University of Wisconsin bulletin:
Go here for information about how to prepare plant samples and where to take or send them: