Why does your Thuja occidentalis have brown leaf tips? Diagnose the cause and fix it with our step-by-step guide.
Arborvitae have shallow root systems that are highly susceptible to moisture deficits. When the soil dries out completely, the plant cannot transport water to the furthest extremities, resulting in desiccation of the branch tips.
Sodium chloride from road salt or coastal spray accumulates on the foliage of Thuja occidentalis. This creates osmotic stress that draws water out of the needles, causing characteristic browning starting at the tips.
Excessive moisture combined with poor air circulation can promote fungal pathogens. These organisms attack the tender new growth, causing tips to turn brown and eventually leading to twig dieback.
In cold climates, frozen roots cannot replace the water lost through transpiration on sunny, windy winter days. This leads to 'winter burn,' where the tips of the evergreen foliage turn a distinct rusty brown.
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