The answer to 'hedge dying' is that there are several common causes, including improper watering, disease, pests, or environmental stress. Symptoms may include wilting, discolored leaves, and dieback. Solutions can range from adjusting watering and mulching to treating disease or pests, or in severe cases, replacing the hedge.
If you're unsure of the cause or how to properly treat a dying hedge, it's best to consult a professional landscaper. They can diagnose the issue and recommend the appropriate course of action to revive or replace the hedge.