What is causing my holly to go bald in one specific area?
This well established holly looks fine at the front (picture 1) but is suffering from die back towards the top at the rear of the bush. The impact is on the east facing side, is about 2 feet square and about 5-7 feet high (picture 2). The rest of the bush appears healthy. The wildlife in my garden, particularly the birds, love the bush so I would hate to lose it. Any ideas what is causing this and how I can help the bush to recover?