What does yellow leaves on my boxwood shrub mean?
What Does Yellow Leaves on My Boxwood Shrub Mean
Certified GKH Gardening Expert
It could be a few things. One is mites. They are too small to see, but do cause damage like that. Another is a fungus. Again, there are several kinds, blight fungus being the most probable cause. Finally, if it's been newly planted, then it could be suffering from transplant shock. Giving it additional water will help with this.
Fortunately, there is an organic solution that treats mites and fungus (and other insect pests, just in case). Treat the affected shrubs with neem oil once a week for a month. Here is more information on neem oil:
Either not enough water, or to much water. Is the boxwood well establish? How old is it? I could better answer this if I had a little more to go on.