By University of Illinois Extension serving Jo Daviess, Stephenson and Winnebago counties
Does the white pine in your yard look brown and sickly? If so, no need to be alarmed. What some might confuse as needle dieback caused by some disease or environmental stress or even as fall color, is actually just the tree’s natural fall needle drop.
It can be a startling site, but around this time every year, many evergreens will shed their oldest needles. Although the term evergreen insinuates their leaves will live forever, they really do not. New growth is produced on the outermost part of the branches every year, and as a result, the older, innermost needles begin to become shaded out. These needles eventually die and fall away in the fall.
On some evergreens, this needle drop is more noticeable than others. Older needles may turn yellow, red or brown, and some may even go unnoticed before dropping. The inner needles of white pines will suddenly turn yellow and drop after about seven to 10 days. Older arborvitae leaves, on the other hand, turn a reddish brown. This year, the needle discoloration on white pines is very noticeable, which is likely because of the drought stress of this summer. Natural needle discoloration may be more noticeable on trees that have experienced root stress because of less-than-optimal growing conditions.
If this discoloration or needle drop occurs earlier in the season or on the new growth, that may be a cause of concern. This natural foliage drop may be distinguished from other damage as a result of disease or stress by its appearance over the entire tree and the similar appearance of neighboring trees of the same species.
Remember, too, that there are actually a few types of conifers that shed all their needles every year. These deciduous conifers include larch, bald cypress and dawn redwood. So don’t mistake that natural needle drop for a dead tree.
Call the University of Illinois Extension Master Gardener volunteers at your local extension office with further questions, or post your questions on the University of Illinois Extension Horticulture-Northwest Illinois Facebook page at http://www.facebook.com/northwestillinoishorticulture.
University of Illinois Extension provides educational programs and research-based information to help Illinois residents improve their quality of life, develop skills and solve problems. If you need a reasonable accommodation to participate in programs, call the University of Illinois Extension office in Winnebago County at (815) 986-4357.
From the Oct. 24-30, 2012, issue