Evergreens dying

Hi Anne: I have 2 arbervities and a Japanese golden henoki (not sure on spelling) that are dying from the inside out. They start turning brown near the trunk then moves toward the end of the branch but are still alive at the ends. I’ve replaced them once before for the same problem. Any ideas – any way to save them? Thanks – Roger E.

Anne's Response:

There are several things that may be causing problems with your evergreens. Dry weather and “voles” eating the roots are causing problems in some Raleigh neighborhoods. Hot afternoon sun does not help. The insect problems usually leave “webs” around the brown needles or make damaging marks on it. Making sure there is good organic matter content in the soil to retain moisture does help. Keeping plants mulched but making sure the mulch does not get close to the trunks to encourage vole damage is important. The symptoms you describe are a natural growth pattern for most evergreens. As the plant grows the growth on the inside of the plant “ages out”; it turns brown and in most plants eventually falls off. In most cases new green growth does not develop on the interior stems. Some evergreens retain the “old, brown needles” for several years. The tip ends of the plant continue to grow and stay green. Excess nitrogen in the soil can cause rapid growth. It would be a good idea to collect a soil sample and have it tested for nutrient level and pH.