Seasonal Needle Drop of Evergreens
Written by: Jean Ferdinandsen – Certified Arborist WI-0149A
The word “evergreen” used to describe conifers, is not actually accurate. It is normal for some needles on conifers to turn yellow and drop from the tree.
Needles of conifers have varying life spans. They age, turn yellow, then brown and drop off the tree after one to several years. The change can be gradual or dramatic.
White pines show the most dramatic seasonal needle drop in fall, whereas spruce and fir tend to drop needles progressively in a more gradual, less noticeable process. Arborvitae shed whole branchlets, which may remain on the tree for some time. Yews tend to drop needles in early summer. On bald cypress, dawn redwoods, and larch, ALL the needles turn brown and fall from the tree in autumn.
The pattern of seasonal needle loss is typically a gradual discoloration and eventual loss of inner needles from the top of the tree down. In contrast, fungal disease may affect the newer or outermost needles, and start from the bottom up. Seasonal needle drop can be alarming and may lead one to think a tree is diseased or has an insect problem.
Environmental stresses such as drought and high temperatures may cause a greater than normal loss of needles. Watering as needed up until the ground freezes is important to maintain healthy evergreens.
Knowing that seasonal needle drop is normal, is the first step to determining what may be happening. The Certified Arborists at Wachtel Tree Science are always available to help you make sure.