Winter Browning of Green Giant Arborvitae Thuja

New owners of Green Giant Arborvitae often panic when they look at their trees after the first cold as they turn golden brown.

All evergreens need to absorb water even during the Winter, although they will do so at a much slower rate than in the Summer. When the weather turns freezing, the trees slow their metabolic rate and water absorption is well. The dehydrated and golden brown appearance of the tree is a protective response and the trees will turn fully green once the warm weather returns.

By-the-way, dehydration & browning is a universal response from all evergreens in the Winter season, but the extent of weight loss and browning is plant and condition specific. Often, but not always, when container grown, smaller plants in smaller containers will turn more brown than larger plants in larger containers. We believe that the plant browning as a protective response is driven by soil temperature and therefore by water accessibility. Perhaps the decreasing osmotic pressure reduces the pressure and water availability in the Xylem which closes the Stomata and reduces water demand and metabolic rate until ground and water temperature increases..