Plants that appear to be doing well in the spring, but then crash in the heat of summer could be missing something – literally. We have received a number of different woody plants showing poor vigor, reduced growth, sun scald on the leaves or stems, small leaves, and branch dieback, all leading to a slow decline of the entire plant and eventual death.
A close inspection at the base of the trunk or main stem showed the bark and underlying tissues had been stripped, partially or completely around the stem. Plants need these tissues to transport water absorbed by the roots to the upper parts of the plant. When missing, the plant cannot get enough water to meets it needs, and the plant begins to shut down. Symptoms usually appear most obviously in the summer, when water demand is high.
Voles are often the cause, although rabbits, some insects, and gophers can also damage plants. Voles feed at the base of woody stems under winter snows, where their damage is not visible. Prevention consists of protecting the stems physically, for individual trees, with a wire barrier, or by trapping. For more information on vole management, see https://catalog.extension.oregonstate.edu/pnw627.
Young hazelnut stem.
Girdling is apparent on this conifer trunk.