Don't Be Alarmed by Fall Needle Drop
FOR IMMEDIATE RELEASE
October 11, 2012
Is your white pine dropping needles? 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 that 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, like in the picture, will suddenly turn yellow and drop after about 7-10 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 due to the drought stress of this summer. Natural needle discoloration may be more noticeable on trees that have experienced root stress due to 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 due to 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 Master Gardeners 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.
Source: Candice Miller, Extension Educator, Horticulture, firstname.lastname@example.org