Unfortunately boxwood varieties grown at historic sites like Mt. Vernon are probably not the modern disease-resistant cultivars (unless they've had to replace them over the years and changed cultivars). While no boxwood variety is immune to problems, cultivars introduced in the past decade are more naturally resistant to infection by Boxwood Blight and leaf-feeding damage by Boxwood Leafminer, the latter being the primary insect pest of boxwood in our region.

We don't see Boxwood Blight symptoms in the photos, though we don't have enough of a close-up view to be certain. One classic indication of this pathogen is the rapid and complete defoliation of the shrub, beginning at the point of infection (often lower branches or one side of a shrub), and leaves may fall while still green and not yet brown/dried. The damage we see here more closely resembles Volutella Blight (which is more widespread, as it takes advantage of plants that were stressed or injured) in addition to decline due to environmental factors (not a pest or disease). You can use the information on our boxwood diagnostic page to narrow-down potential causes. Feel free to send us close-up pictures of suspected symptoms if you'd like feedback.

We see a roof downspout in one photo; does that empty there, next to the boxwood, or does it extend further away to drain? Boxwood have very shallow and sensitive roots and aren't very tolerant of oxygen-deprived conditions created by soil that gets too wet. Is any landscape fabric used under the mulch on that planting bed? If so, the shrubs would fare better if it was removed, since that also may reduce soil oxygen content and interfere with how much rainwater can reach the root zone. Last year much of Maryland experienced prolonged drought, and unless monitored regularly for watering needs, even established shrubs became stressed and may have had root damage as a result. (Compromised roots cause branch or foliage dieback since they're can't support all of the above-ground growth.)

Branches dead from presumed Volutella (or whatever the cause) will need to be pruned off. Given that this leaves a patchy, irregular canopy, the only way to regain the shrub's even, dense shape is to either wait several years for fill-in growth or to prune all branches back drastically to force basal growth to start filling in. This process will similar take a few years, given the slow growth rate of boxwood, but is the only option short of outright replacement. If you do replace the shrubs, look for either non-boxwood species or cultivars of boxwood that tout good resistance to Boxwood Blight and leafminer. A photo example of a boxwood that underwent a drastic pruning and is beginning to regrow is attached.

If you decide to replace the plants with another shrub species, we can share some ideas if you want, though we'd need to know more about the site conditions first. (How much direct summer sun it may receive; how well the soil drains or if an overhang keeps it drier; if deer browse in the yard; what the desired mature size is without having to rely on pruning to restrain growth.)

Miri

Not sure if you saw these photos of the English Boxwoods—the photo attached to the reply was a newer American boxwood my husband had pruned……that is not

The one I am so worried about.  These attached photos are.

 

Thanks again,

Sarah

 

Hello Sarah,

The fact that decline has been slow/gradual suggests Boxwood Blight is not present, but it still may be Volutella Blight. We received two of the photos earlier in the current group of four; of the new two, the image file named "boxwood 1" shows a shrub in the foreground we'd not suggest saving since it looks too far gone. The other one, more visible in "boxwood 2," might recuperate if the dead areas are trimmed out and it's given time to fill in (or you try the drastic cut-back technique, which will similarly take a while to grow out of). The specimen in "boxwood in front yard" looks pretty good, at least what we can make out in the photo since the file isn't large enough to zoom-in. "Boxwood 3" also looks pretty good.

We'll see what is visible in the pending close-up images and try to determine if any other diagnoses present themselves.

Miri

Hello Again!

 

More pictures of the sad Bethesda Boxwoods that we love but am not sure we can save.   If you could have seen them in their full bushy days!   I kept thinking they had winter stress but it appears it is this nasty Volutella Blight. 

The pictures here are close up of the leaves and stems of the boxwoods that are closest to the house and the drainage system which actually we had connected to underground drains that go away from the  house and the boxwoods

To a lower underground drainage system.    The other vents are heating system release vents and I will have to check and see what if anything ever comes out of them. 

 

If there is anything we can do to help these boxwoods survive and thrive again--- we’ll do it but if not—we’ll take them out and replace them with something else you might suggest would do well.

 

Thanks again,

Sarah  

Winter stress might have preceded an infection like Volutella, and more than one condition could always be overlapping as well. The close-up photo of all-dead foliage isn't quite in focus and all-dead growth isn't as diagnostic since it lacks key symptoms that appear as tissues are starting to die off. Using information in the pages we linked to previously, you can inspect the leaves for Volutella spores, especially after/during a period of wet weather. Still, that won't change the fact that dead growth needs to be pruned off and the entire shrub might need cutting-back drastically to force renewed growth that will be more even, dense, and vigorous. (Granted, it will be a slow process, and nothing will change that since boxwoods grow slowly by nature.)

There is no other form of intervention right now that will be of any help -- no fungicide will provide any benefit, and they should not need fertilizer either -- and you can continue to monitor the root zones for watering needs as we move into spring and summer if you're keeping the plant(s) and waiting for new growth.

Miri

Dear Miri,

 

I found these pictures which I assume show the spores on leaves and on the stems and branches.  I will cut back the ground the dead stems and branches and remove any other dead leaves/branches on the ground.

 

Thank you again for your help and sharing your time and knowledge.  I have learned a lot and do appreciate you and all the other wonderful volunteers and staff with the Maryland Extension program.   

I am a proud TERP and know our University of Maryland College Park is wonderful example of a Land Grant University!  I loved volunteering in the stables on campus ……many, many years ago.   Class of 1981. 

 

Thanks again and all the very best,

Sarah

Leafless branch stubs may or may not be dead...it's too early to tell because if they are capable of leafing-out, they will not do so for another few weeks. Information about branch wood discoloration due to the infection can be found in the linked Ohio State page about Volutella damage, which may allow you to tell how far down the leafless branches to prune.

Volutella spores will be a pinkish or orange-salmon colored grainy-looking substance on the back of infected leaves.

Miri