Yellowing Boxwood Leaves - Ask Extension
Hello- Recently, I have noticed several of the leaves on the boxwoods outside of my house have leaves that are turning yellow and brown. It isn't aff...
Knowledgebase
Yellowing Boxwood Leaves #877539
Asked July 16, 2024, 7:28 PM EDT
Hello-
Recently, I have noticed several of the leaves on the boxwoods outside of my house have leaves that are turning yellow and brown. It isn't affecting all of the leaves, just a seemingly random few. Reading though UMD's boxwood management page, I think it may be winter damage, boxwood mites, or something else. I have included some photos of the damage. Additionally, I think there is some thinning at the top of the plants. Can you please look at the attached pictures and let me know what you think the issue is?
Thank you for the help,
Matt
Harford County Maryland
Expert Response
Hello Matt,
This looks like classic Boxwood Leafminer damage, perhaps the most common insect pest of boxwoods in our region. There is a small, unconcerning amount of Boxwood Psyllid damage as well, but nothing needs to be done about it, and we don't see any mite feeding damage. Options for managing leafminers include pruning out the affected growth (which may entail removing several inches of all the branch tips, reducing the plant's size for the time being) or using systemic insecticide (absorbed through either leaves or roots) that kill the larvae inside the leaves, once they resume feeding. They go semi-dormant and pause development when it's hot in midsummer, so they are not feeding right now, even though the plant's stress from summer drought and heat might be making the existing symptoms more prominent.
The shrubs (especially the one on the corner) are in a stressful environment, having limited root space, being very close to the building wall and bordered by the sidewalk. To help reduce their overall stress during this drought, make sure they are being monitored for watering needs by feeling the soil moisture a few inches deep and watering well once it becomes somewhat dry to the touch at that depth.
Miri
This looks like classic Boxwood Leafminer damage, perhaps the most common insect pest of boxwoods in our region. There is a small, unconcerning amount of Boxwood Psyllid damage as well, but nothing needs to be done about it, and we don't see any mite feeding damage. Options for managing leafminers include pruning out the affected growth (which may entail removing several inches of all the branch tips, reducing the plant's size for the time being) or using systemic insecticide (absorbed through either leaves or roots) that kill the larvae inside the leaves, once they resume feeding. They go semi-dormant and pause development when it's hot in midsummer, so they are not feeding right now, even though the plant's stress from summer drought and heat might be making the existing symptoms more prominent.
The shrubs (especially the one on the corner) are in a stressful environment, having limited root space, being very close to the building wall and bordered by the sidewalk. To help reduce their overall stress during this drought, make sure they are being monitored for watering needs by feeling the soil moisture a few inches deep and watering well once it becomes somewhat dry to the touch at that depth.
Miri
