help identifying boxwood problems - Ask Extension
Hello,
I have a boxwood that has a small portion that just recently defoliated. I have read that boxwood blight can cause defoliation. I don't thin...
Knowledgebase
help identifying boxwood problems #786866
Asked April 14, 2022, 7:32 PM EDT
Hello,
I have a boxwood that has a small portion that just recently defoliated. I have read that boxwood blight can cause defoliation. I don't think I see the spots on the leaves or streaks on the stems that are characteristic of the blight, but I am really not sure. I have included three photos, all of which are from the same plant.
Do you have any insight as to whether it is boxwood blight or not? And if not, and ideas of what it could be?
Thank you very much for your time.
-Ella
District of Columbia County District of Columbia
Expert Response
Hello Ella,
Defoliation of infected stems is one of the classic symptoms of boxwood blight, though defoliation can occur with other ailments as well. If leaf spots and dark stem lesions are also detected with defoliation, these three symptoms co-occurring together do strongly suggest boxwood blight is to blame. Unfortunately, this disease is becoming fairly widespread in the eastern U.S. It's difficult for us to see clear signs of stem infection in the photos, though there definitely does seem to be some type of leaf spotting occurring. You can compare what you're seeing with the images and information on our Boxwood Blight and Boxwood...Problems pages, which discuss other boxwood ailments and reactions to stress.
Have any new boxwood, pachysandra, or sweetbox (Sarcococca) plants been added to the yard in the past year or so? (Or do you decorate with cut boxwood stems for the winter holidays?) Any of these scenarios might have accidentally introduced blight spores into the landscape of these items were contaminated, though spores can also blow in from nearby hotspots of infection or be tracked-in on contaminated shoes or equipment of a landscaper. Although our HGIC office don't collect plant samples, if you do use a landscaping service, they may be able to send samples to a University lab for testing to confirm if boxwood blight is responsible.
If confirmed, you can then determine if plant removal is more practical than treatment with a fungicide, depending on how widespread the symptoms appear to be. (A fungicide won't cure existing infection or directly reverse its damage; it can only help to prevent that infection from spreading to healthy tissues. One or more applications per year would be needed to keep up this protection, which is why replacement is simpler and cheaper.) Some boxwood cultivars are quite resistant to boxwood blight (and other common boxwood problems), though none are immune.
Miri
Defoliation of infected stems is one of the classic symptoms of boxwood blight, though defoliation can occur with other ailments as well. If leaf spots and dark stem lesions are also detected with defoliation, these three symptoms co-occurring together do strongly suggest boxwood blight is to blame. Unfortunately, this disease is becoming fairly widespread in the eastern U.S. It's difficult for us to see clear signs of stem infection in the photos, though there definitely does seem to be some type of leaf spotting occurring. You can compare what you're seeing with the images and information on our Boxwood Blight and Boxwood...Problems pages, which discuss other boxwood ailments and reactions to stress.
Have any new boxwood, pachysandra, or sweetbox (Sarcococca) plants been added to the yard in the past year or so? (Or do you decorate with cut boxwood stems for the winter holidays?) Any of these scenarios might have accidentally introduced blight spores into the landscape of these items were contaminated, though spores can also blow in from nearby hotspots of infection or be tracked-in on contaminated shoes or equipment of a landscaper. Although our HGIC office don't collect plant samples, if you do use a landscaping service, they may be able to send samples to a University lab for testing to confirm if boxwood blight is responsible.
If confirmed, you can then determine if plant removal is more practical than treatment with a fungicide, depending on how widespread the symptoms appear to be. (A fungicide won't cure existing infection or directly reverse its damage; it can only help to prevent that infection from spreading to healthy tissues. One or more applications per year would be needed to keep up this protection, which is why replacement is simpler and cheaper.) Some boxwood cultivars are quite resistant to boxwood blight (and other common boxwood problems), though none are immune.
Miri
