Boxwood Plague - Ask Extension
Hi:
I've had boxwoods planted around my home for several years because I believed they were impossible to kill, even with my black thumb. They liv...
Knowledgebase
Boxwood Plague #934132
Asked June 04, 2026, 8:30 AM EDT
Hi:
I've had boxwoods planted around my home for several years because I believed they were impossible to kill, even with my black thumb. They lived up to that reputation until late last summer when three of them planted close together suddenly browned. The remaining dozen or so seemed fine. Over the next month, whatever this was progressed all the way around the house and killed every boxwood, but only this variety. It even wiped out a few of my neighbor's plants across the street. It left the taller, conical shaped versions intact. I've attached a funeral portrait of one of the shrubs from last year. Any ideas what caused this? And what should I do, if anything, before replanting? I can't see spending the time and money to replace them for a repeat performance this fall.
Thanks!
Eaton County Michigan
Expert Response
Hello
The resolution on your pictures isn’t quite clear enough for me to see the branches clearly and identify exactly what happened. But this is likely boxwood blight. If you see blackening along the stems, then that is one of the indications of boxwood blight disease. There is no cure for Boxwood blight and, as you know, it can spread quickly and decimate the shrubs.
There are several other issues with boxwood as well. So, we no longer recommend planting them.
Bulletin that summarizes the current issues- https://www.canr.msu.edu/resources/whats-wrong-with-my-boxwood-common-issues-and-solutions
Box tree moth a new invasive insect-
https://www.canr.msu.edu/resources/insecticide-options-for-box-tree-moth-management-ir4-project
And this- https://www.canr.msu.edu/news/safeguard-against-spreading-the-invasive-box-tree-moth
boxwood blight— This disease can look like winter kill as well, so it is important to correctly identify what the issue is, since boxwood blight has no ‘cure’ on shrubs that are already infected.
Protect healthy plants that were located near diseased plants by using a fungicide.
Fungicides are only recommended on sites where boxwood blight has been confirmed.
If disease is detected, surrounding healthy plants should be protected with fungicides. Homeowners should use chlorothalonil at 10-to 21-day intervals (refer to label) as long as conditions are conducive for disease.
More details here—
https://plantpathology.mgcafe.uky.edu/files/ppfs-or-w-20.pdf
https://www.canr.msu.edu/news/preventing-the-spread-of-boxwood-blight-in-landscapes
Finally, here is a bulletin should you decide to replace your boxwood with hardier shrubs with less disease and pest issues. Note that we recommend planting a variety of species so that, in future when new diseases and pests arrive, you don’t lose a whole planting.
https://www.canr.msu.edu/news/beyond-boxwood-alternative-landscape-shrubs-for-michigan-gardeners
To confirm what your shrubs have you may attach pictures here of 2-3 branches clipped off and laid on plain smooth surface. ( Please don’t use paper towels as the texture confuses the camera focus).
Or, you may submit pictures and branch samples to MSU Plant and Pest Diagnostic lab for assessment. The instructions and fee schedule for their service is on the website. https://www.canr.msu.edu/pestid/
The resolution on your pictures isn’t quite clear enough for me to see the branches clearly and identify exactly what happened. But this is likely boxwood blight. If you see blackening along the stems, then that is one of the indications of boxwood blight disease. There is no cure for Boxwood blight and, as you know, it can spread quickly and decimate the shrubs.
There are several other issues with boxwood as well. So, we no longer recommend planting them.
Bulletin that summarizes the current issues- https://www.canr.msu.edu/resources/whats-wrong-with-my-boxwood-common-issues-and-solutions
Box tree moth a new invasive insect-
https://www.canr.msu.edu/resources/insecticide-options-for-box-tree-moth-management-ir4-project
And this- https://www.canr.msu.edu/news/safeguard-against-spreading-the-invasive-box-tree-moth
boxwood blight— This disease can look like winter kill as well, so it is important to correctly identify what the issue is, since boxwood blight has no ‘cure’ on shrubs that are already infected.
Protect healthy plants that were located near diseased plants by using a fungicide.
Fungicides are only recommended on sites where boxwood blight has been confirmed.
If disease is detected, surrounding healthy plants should be protected with fungicides. Homeowners should use chlorothalonil at 10-to 21-day intervals (refer to label) as long as conditions are conducive for disease.
More details here—
https://plantpathology.mgcafe.uky.edu/files/ppfs-or-w-20.pdf
https://www.canr.msu.edu/news/preventing-the-spread-of-boxwood-blight-in-landscapes
Finally, here is a bulletin should you decide to replace your boxwood with hardier shrubs with less disease and pest issues. Note that we recommend planting a variety of species so that, in future when new diseases and pests arrive, you don’t lose a whole planting.
https://www.canr.msu.edu/news/beyond-boxwood-alternative-landscape-shrubs-for-michigan-gardeners
To confirm what your shrubs have you may attach pictures here of 2-3 branches clipped off and laid on plain smooth surface. ( Please don’t use paper towels as the texture confuses the camera focus).
Or, you may submit pictures and branch samples to MSU Plant and Pest Diagnostic lab for assessment. The instructions and fee schedule for their service is on the website. https://www.canr.msu.edu/pestid/
Hi:
Thanks for the quick response. Here are the photos you requested.
Kent
Thank you.
I don’t see the characteristic black lesions on the stems for boxwood blight.
Before planting any replacement box, please submit these photos, and some additional ones showing brown leaves and still green leaves, if any, to the MSU lab. Pictures against a plain sheet of paper, such as printer paper, would be better than cement background.
Take a picture of the conical one that survived, along with a close up of the conical shrubs branch with green leaves to send to the lab, too. Include your watering history( how often, how long, inground or above ground system?), what month the first 3 died and what month the remainder died. Email the lab all this info at <personal data hidden>
An email consultation is free.
The branches could be what is left after winter kill, drought stress or box tree moth. Blight or root rot is still a possibility.
The professional horticulturalists and pathologists at the lab may request you submit samples, including root samples.
Sorry I couldn’t give an exact diagnosis.
Regards,
Laura S.
I don’t see the characteristic black lesions on the stems for boxwood blight.
Before planting any replacement box, please submit these photos, and some additional ones showing brown leaves and still green leaves, if any, to the MSU lab. Pictures against a plain sheet of paper, such as printer paper, would be better than cement background.
Take a picture of the conical one that survived, along with a close up of the conical shrubs branch with green leaves to send to the lab, too. Include your watering history( how often, how long, inground or above ground system?), what month the first 3 died and what month the remainder died. Email the lab all this info at <personal data hidden>
An email consultation is free.
The branches could be what is left after winter kill, drought stress or box tree moth. Blight or root rot is still a possibility.
The professional horticulturalists and pathologists at the lab may request you submit samples, including root samples.
Sorry I couldn’t give an exact diagnosis.
Regards,
Laura S.
