Q: Is this boxwood blight?
A: My plant pathology friend Jean Williams-Woodward says “The plant looks like it is dying from a root problem, not boxwood blight. It is planted next to a stone walkway. It looks like the roots are suffering from too much water and possibly root disease.
The initial symptom of boxwood blight is round, tan leaf spots with a dark border. Once the spot develops, the leaves turn tan and drop from the plant. The area beneath the plant would be littered with fallen leaves.
In the image, I don’t see any leaf spots and the leaves are remaining on the plant. American boxwoods are moderately susceptible to boxwood blight. If one had it this bad, then the others would be showing leaf spotting and branch dieback as well.
Check the roots and lower stem on this plant to see if it wasn’t planted too deeply or is getting too much water or not enough and is drying out due to radiant heat from the walkway. Note that garden hose irrigation may not have allowed for the water to penetrate the soil deeply enough to keep the roots alive. Something other than boxwood blight is causing this plant’s death.”