Lately we have gotten quite a few calls about a white substance on a wide range of plants. This white substance is called powdery mildew and our recent weather conditions have created the perfect environment for this fungus to thrive. Powdery mildew thrives in hot and humid weather, especially if the weather conditions persist for more than 3 days in a row.
powdery mildew on plant leaf
Powdery Mildew
  • What does it look like and how do I know if I have it?

Your plant will have a white powdery substance on the top of the leaf. The leaves may also start to curl and twist in affected areas.

  • What plants commonly get powdery mildew?

This fungus is one of the most widespread and common diseases in plants. Some of the more common infected plants are Roses, Lilacs, Bee Balm, Serviceberry, Crabapples, and Burning bushes.

  • Are my plants dying?

No, this is purely aesthetic and only grows on the surface of the plant. Powdery mildew does not infect the tissue and is not killing the plant. With that being said, the plant my drop its leaves early if it fully covered.

  • How do I get rid of it?

Trim the areas of the plant that are affected by the powdery mildew and remove the debris from the area (do not compost this debris). Do not use overhead watering. Place the hose at the base of the plant instead when watering. There are also multiple chemical sprays that can be purchased at home improvement or garden centers that will help resolve the problem as well. For a more naturalistic approach, baking soda mixed in water may help solve the problem as well.