Asked September 27, 2020, 9:45 PM EDT
I am wondering if I have multiple issues with my burning bush. I sent a question to you last year with a photo that looked like a tent caterpillar. These are recent photos. Exfoliation did not improve and seem to have spidermites in five of my 10 hedge bushes. Also wondering if there are caterpillars eating the chunks of leaves and defoliating. Since it is fall, wondering if I should do severe pruning in late winter. Also should I treat for both mites and caterpillars now? Very frustrating. Mainly used water and insecticidal soap this past year to no avail. Any advice is welcome again.
Jefferson County Kentucky
Euonymus usually are hardy plants, even in the face of adversity. They will accept many different growing conditions. There are a few things that can cause problems though, including spider mites. From the photos above the corner plant has suffered the most damage. The corner is going to receive the most damage in any hedge situation so step back and look at the planting. The plants are planted close to the side walk making the roots of the corner plant more constricted. Any wind, rain, or even people walking by can physically damage that plant. The plants are close (hedges usually are) and are of an age to grow into each other so they are competing for light. water, nutrients and space for roots. The pruning in the past has been into hard old wood and as long as there are other branches the plant can continue growing, it will and in that direction. A hard prune for this plant may help solve that but it will take several years to grow out. If you hard prune the entire hedge you may have bare sticks for a few seasons.
Spider mites are actually tiny spiders that feed on plants by sucking the sap and chlorophyll from leaves, making them appear to fade or look like they are dying. Spider mites quickly become resistant to most insecticides that work as toxins. Insecticidal soap works differently by covering the mite and smothering the mite. Insecticidal soap also starts to dissolve the soft tissue of the mite leaving internal organs exposed. Because insecticidal soaps are organic and do not leave toxins behind we recommend them. Follow the label instructions and spray as often as possible to eradicate the mites.
Beetles and caterpillars cause damage at various times. They may be difficult to control as beetles have wings and can easily fly from plant to plant. Caterpillars feed and fall to the ground to pupate into adults later so they are also difficult to control.
Please call our office so we can discuss the complicated issues of a hedge with several problems.
Let me know if I can help you further!
Jefferson County Cooperative Extension Service
4200 Gardiner View Avenue
Louisville KY 40213