looks like they could benefit from renewal pruning... only 2'' of green at the tips. Cut out 1/3 of the old branches. With boxwood, renewal is usually a few year period. Could be drought stress as stated above. Take some soil and some infected branches to your extension agent. Sterilize your tools after trimming just in case.
Does anyone else see the yellowing around the edges of the green leaves??? Chlorosis? Check the soil.
Landscape management, design, and installation
Horticulturalist with Specialization in Landscape Management
25 years old 7 years in business ownership