Q: Every year, my boxwoods change from a nice green color to a purple-bronze color in the winter. Is there any way to prevent this?

A: Boxwoods are beautiful shrubs, but the bronzy discoloration you describe is common. Usually, it has something to do with the shrub’s root system. Boxwoods have a shallow root system. That means that they are very susceptible to both too much and too little water during the growing season. If the roots have been weakened during the summer, discoloration in the winter is the result.

Another problem could be an infestation by nematodes. These microscopic worms feed on boxwood roots, causing weakness and a change in leaf color. You should examine the soil around your boxwoods to see if water problems could be causing your problem. Nematodes can be detected by bringing a sample of the soil to your county extension service office in the summer for a nematode assay.

If you decide that these shrubs are beyond saving, replace them with ‘Green Velvet’ or ‘Green Mountain’ boxwoods. These selections are resistant to root problems, and they do not change color when stressed. Make sure to plant them in well-drained soil to avoid future difficulties.