Winter Woes On Woody Landscape Plants: Winter Drying

From the Kentucky Pest News

The UK Plant Disease Diagnostic Laboratory (PDDL) has received many broadleaf and needled evergreen samples with discolored foliage recently. Despite relatively mild weather during much of the winter thus far, extremely low temperatures, low humidity, and strong winds during the third week of December 2022 resulted in a range of winter injury symptoms in landscape plants. Furthermore, other environmental and cultural stress factors preceded the severe weather in many cases and have contributed to the extent of damage visible now.

Symptoms

Since the beginning of January, most of the samples with winter injury that have arrived in the PDDL have shown symptoms of winter drying. On broadleaf evergreens (boxwood, cherry laurel, holly, magnolia, rhododendron, etc.), symptoms typically include marginal leaf scorch, irregular spotting, complete browning of the leaves, and occasionally extensive leaf drop. Conifer (arborvitae, Leyland cypress, Cryptomeria, juniper, etc.) symptoms include pale, bronze or brown needles or needle tips, particularly on the exterior foliage and branch tips. Symptoms are often more noticeable on the wind-exposed side of affected plants.

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