The answer to 'hedge brown patches' is that there are several common causes, including drought stress, disease, pests, and improper pruning. Symptoms include discolored, wilting, or dying patches in the hedge. Solutions can range from adjusting watering, applying fungicides or pesticides, or pruning out affected areas.
For minor issues, homeowners may be able to address the problem themselves. However, for severe or persistent hedge problems, it's best to consult a professional landscaper who can properly diagnose and treat the issue.