I planted 3 Camellias about 10 yrs ago, and all grew great for about 7 years, then one started to die one branch at a time. I cut the dead branch off, then another started dying one branch at a time. The first one died completely, and now the second one. During this time, the parts that were not dead continued to bloom. Any ideas what causes this, and what can I do to prevent the third one from dying?