I have three dwarf boxwoods that are showing decline. I’ve read about some of the problems with boxwood, but am uncertain which is the likely culprit and what to do about it. Before we give up on these shrubs, I wanted to see if you could identify the problem from these photos and whether there is anything that can be done to rejuvenate these plants.
Montgomery County Maryland
We looked at your photos. We notice several insect pests of boxwood that you may may be dealing with such as boxwood leafminer (middle and right photo) https://extension.umd.edu/hgic/boxwood-leafminer-shrubs,
possible psyllids https://extension.umd.edu/hgic/topics/boxwood-psyllid-shrubs
and boxwood mites (right photo - white stippling) https://extension.umd.edu/hgic/topics/boxwood-preventing-and-managing-common-pests-and-diseases#mite
The least toxic way to manage these pests would be to thin and prune back the shrubs by about one third. Thus you can avoid chemicals altogether. This will also help reduce problems for next year.
Please look at this link and video to see how to prune your boxwoods. https://extension.umd.edu/hgic/topics/boxwood-preventing-and-managing-common-pests-and-diseases
Monitor the health of the plants this season and look for new growth. You can send us photos if you notice additional symptoms.