I am very concerned that my boxwoods have Boxwood Blight. We just noticed it in the last week, but were out of town for 2 weeks before that. If it is Boxwood Blight, how do I take care of it? I have 5 boxwoods that go across my front porch, and it looks like the first 4 are all infected. If it is not Boxwood Blight, do you know what is killing my boxwoods so quickly?
Montgomery County Maryland
Unfortunately, this does appear to be boxwood blight. The black lesions on the leaves and rapid defoliation from the base of the plants are symptoms of this disease. https://marylandgrows.umd.edu/2019/04/01/boxwood-blight-in-maryland/
There is nothing available that will cure boxwood blight. You will have to make a decision. You can either remove and replace the plants with other shrubs that are not in the boxwood family, or, you can prune out the affected portions of the plants and then you will have to start a spray program to manage the disease. Fungicide applications would have to be applied repeatedly, on a 7- to 14-day interval, depending on the fungicide product label instructions. A fungicide would help to manage the symptoms but it will not cure the plants of the disease.
The best current information available for homeowners on managing boxwood blight is provided in this publication from Virginia Cooperative Extension. https://www.pubs.ext.vt.edu/content/dam/pubs_ext_vt_edu/PPWS/PPWS-29/PPWS-29-pdf.pdf
If we decide to fight the blight, do we need to spray with fungicide all year round, or just during the growing season?
You will need to spray with fungicide during the growing season, which can stretch from March through November.