We have received numerous calls about yellow needles in various evergreens. This is a naturally occuring event that seems to be more prevelant this year. This is an excerpt from The University of Maryland Extension newsletter that goes to Arborists, Landscape Managers & Nursery Managers.
Fall Color is Coming On – Especially Evergreens
Karen Rane and I (Stanton Gill, Extension Specialist) are receiving a lot of pictures of arborvitaes, white pines and other evergreens with yellowing needles/leaves. The landscape managers sending these photos are concerned that the plants are dying. Actually, what is happening is that this is the older growth the is going into typical fall coloration. After a very hot summer (record number of days above 100 F this summer) many of these evergreens were under stress and are expressing heavy yellowing and browning of older growth this fall. There is nothing you need to do at this point.
If you feel that your trees are not showing this type of pattern please give us a call and we will come and inspect.
And have no fear, these lost needles will grow back next year.
Click here to view the PDF of this article.
Source: SPS