“What’s that white stuff covering the leaves of my lilacs? It looks like someone attacked them with a dusting of baby powder!”

Powdery mildew

Baby powder or nasty fungus? Powdery mildew covers plants with white blotches.

Photo Credit: Donna W. Moramarco

It’s time to take a closer look at your plants, especially beebalms, peonies, phlox, roses and zinnias. Powdery mildew, a nasty fungus, is making its yearly appearance in many gardens and landscapes.

What the heck is powdery mildew? Plain and simple, it’s a garden nuisance that adores the high humidity and excess moisture that comes with summer and can last in fall. Typically, many of us across the US experience summers that are hot and very humid. While we can’t control the weather, there are some things we can do to “manage” powdery mildew in the garden.

If your beds have been hit by this plant attacker, or if you want to stay ahead of the curve and keep powdery mildew at bay, consider the following helpful hints:

  • Whenever possible, avoid wetting the leaves. To keep leaves dry, use a soaker hose.
  • Space plants properly for adequate air circulation (avoid areas that are stagnant, shady and damp).
  • If you want to pick off infected leaves, that’s fine, but do so when foliage is dry.
  • Try to select varieties that are resistant to powdery mildew. Of course, there are no guarantees – resistance does not mean immunity. If in doubt, ask at the garden center before you buy! The plant label may offer some information, as well.
  • Always practice good sanitation in the garden. Rake up and dispose of all fallen leaves and garden debris every autumn.
  • Certain fungicides, chemical or organic, can be used to manage powdery mildew when it’s first detected on your plants. It’s best to check with your local Cooperative Extension office or garden center for a legal recommendation in your state of residence. Be sure to read the label first and follow all directions to a tee!
  • Finally, let’s not spread our garden problems! Common sense reminds us to wash our hands before handling “clean” plants.

Following these tips can help get your garden off to a good mildew-free start this season. (Let’s hope it stays that way!)