Crape myrtle’s flowers don’t open

Powdery mildrew thrives after a wet summer; treat for yellow jackets in house

Your crape myrtle is infected by powdery mildew. Like many fungi, powdery mildew has had a banner year with our abnormally high rainfall. If you have not had this in the past, it suggests your crape myrtle has good disease resistance. It should be back to its usual self next summer — provided we have a more typical dry summer. Prune infected flower heads now to reduce the amount of infectious material that could harm your crape myrtle next year. There are many crape myrtle varieties with excellent disease resistance, so any ones that struggle with powdery mildew year after year should be replaced. Yellow jackets all die when hit with hard freezing temperatures of winter, except for the queen, who leaves and does not return to the hive. However, yellow jackets could stumble into your home for months, if not all winter, because the warmth of your house keeps them alive. Commercial wasp and hornet spray should not harm your family, but the wall’s construction could block the insecticide from reaching the nest effectively. You may need a pest control company. Treat sooner rather than later. The longer the hive population builds, the bigger the resulting mass of dead organic matter, which in turn will attract insects that feed on it.

University of Maryland Extension’s Home and Garden Information Center offers free gardening and pest information at extension.umd.edu/hgic. Click “Ask Maryland’s Gardening Experts” to send questions and photos.