“The leaves of my peonies are covered with what appears to be a white mold, with some of the leaves even turning brown already. What is this problem, and will it affect the plants next year?

Zinnias, pictured, are susceptible to powdery mildew. Other favorite, but vulnerable, flowers include hydrangeas, lilacs, phlox and peonies. Monitor these varieties regularly for symptoms.

What are those spots on my peony? Powdery mildew and leaf blotch. By KEN JOHNSON U of I Extension; Jun 17, 2023 Jun 17, 2023; 0; ... show up fairly regularly on plants during the summer months.

As the growing season progresses, keep an eye out for a white or grayish-white powder on your plants. That's powdery mildew, a fungus that affects a wide range of fruits, Why you should take steps ...