Boxwood Blight

Asked May 15, 2020, 9:17 AM EDT

Hi. I've had many Boxwoods in a hedge planting since 2010. These were trimmed/sheared about 3 weeks ago. Last year we did not do this, although we previously had done it annually. I've noticed brown/ chlorosis on the leaves and brown spots on mainly healthy looking ( non black ) stems. I didn't see any white residue on the underside of the leaves to indicate spores (as the MSU bulletin on the disease suggests). However, it may be early in the course of the disease. I fear that my plants have developed boxwood blight and I wonder if there is anything, short of removing the hundreds of plants, that I can do to salvage them. If you can direct me to an expert to hire I would be very grateful. Thank You. Deanna Master

Wayne County Michigan

1 Response

Hello,

I understand your anxiety about your boxwood. First of all there are several diseases that affect boxwood that can be causing your problem and can be confused. I’m attaching a link which describes the insect pests that attack boxwood and the damage they cause. Go to: https://www.canr.msu.edu/news/boxwood_insect_pests Winter damage can also cause browning of boxwood leaves.

Unfortunately, it is not possible to diagnose the problem from a picture. The leaves must be analyzed by a lab. The Plant and Pest Diagnostic Lab at MSU can do this. To learn how to submit a picture and a sample, go to the link https://www.canr.msu.edu/pestid/

You could contact a certified arborist at https://www.treesaregood.org/ the website of the International Society of Arboriculture but it’s likely that they would have the sample analyzed by the lab also.

Good luck with your boxwood. Thank you for your question.