Knowledgebase

Boxwood Blight #745172

Asked April 19, 2021, 3:40 PM EDT

A number of boxwoods in my yard appear to be dying. Is this boxwood blight? It is my understanding that once the blight has started killing the boxwood, it cannot be saved. What do you recommend that I do to save any boxwoods that still look healthy? Thank you.

Henrico County Virginia

Expert Response

It could be boxwood blight, but I can not see enough detail in the images to make a firm diagnosis. 

I've attached our guidance from our Diagnostic Lab on taking good digital images. The example used in the document is boxwood.  Can you look for the black streaks on the stem and take picture if you find any.

Also, when did you first notice defoliation on the plants?  

Ed Olsen Replied April 19, 2021, 3:51 PM EDT
Attached are three more pictures that might be helpful. We lost 3 boxwoods during the summer of 2019. It was dry that summer and we thought be problem might be lack of water. During the summer of 2020, we were diligent in watering and our boxwoods looked healthy. We noticed this recent defoliation during late fall 2020 and into the winter.

Thank you,
Janis Bunce
On Monday, April 19, 2021, 03:52:58 PM EDT, Ask Extension <<personal data hidden>> wrote:


The Question Asker Replied April 20, 2021, 3:39 PM EDT

Thank you for the additional pictures.  I definitely see boxwood blight stem lesions on picture #3.  I do not see any lesions on picture #4.  And I think I see the beginning of lesions on picture #5.

At this time, I would remove the symptomatic boxwood.  I have attached several files for your reference.  The first is the Boxwood Blight Decision Guide. 

The second is the Best Management Practices for Homeowners with Boxwood Blight.  This publication lists the steps you should take to help protect the potential spread to other boxwood as well as the chemical treatment option.  The chemical treatment option is not just one spray, but repeated applications (at 7- to 14-day intervals, depending on product label and environmental conditions) of fungicides throughout the growing season.

And on a side note, in the original pictures you submitted it looks like the boxwoods are regularly sheared.  Make sure all your equipment (or that of contractors) is also sterilized between plants to avoid potential spread.  And you may want to consider thinning the boxwoods this winter to help allow allow the center of the plant to receive sun and air. Much of the poor health (not related to boxwood blight) of boxwoods is a result of not thinning the plant. Very thick foliage encourages fungal leaf spot diseases and twig blight.

Ed Olsen Replied April 21, 2021, 9:29 AM EDT

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