Q: I have a problem with a butterfly bush that has been very healthy every season until now. One side of it is wilted with all the leaves shriveling. However, all the leaves are still green – none have turned yellow and dropped off. Can you offer any clue as to what might be wrong?
A: When I see leaves that shrivel but are still green, it leads me to suspect one of two causes: insects or herbicide damage. Conversely, drought or lower stem injury would lead to yellow leaves which soon turn brown.
Heavy rain or irrigation can move the chemicals of “weed ‘n feed” products into the root zone of nearby non-target plants. I’ve seen herbicide damage to dogwood, maple and hydrangea in years past. Interrogate your family to be sure no herbicides have been applied in the vicinity.
On the other hand, creatures which hide under leaves and suck sap from the cells can also cause distortion. Use a magnifying glass to examine all surfaces of the butterfly bush leaves. Aphids are relatively large and easy to spot. Spider mites are smaller – they resemble small beige dots walking near the midvein of a leaf. A large population of spider mites can severely stunt a butterfly bush. Control aphids with a blast of water or a garden insecticide spray. If you find spider mites, consult your local Extension office (404-897-6261) for effective chemicals.