Pine Problems

Don't panic if the needles on your white pine turn yellow.

More from Gardening by the Yard
Filed under: Evergreen, Plants

Gardeners often worry when the needles of their white pines turn yellow and then brown in late summer to early fall. Their worry is understandable because most white pines do suffer from a variety of insect and disease problems, many of which cause the needles to turn yellow or brown. However, the yellow needles you see on most white pines in the fall are caused by the natural process of shedding two- to three-year-old needles. And this process happens every year.

So how can you tell the difference between a natural, seasonal process and yellow needles that are the result of something far more sinister? Master gardener Paul James recommends a careful inspection of the needles to determine the cause. For one thing, a number of pests and diseases affect the needles at the tips of the branches. So if the tips of the branches look healthy and there are no visible signs of rust due to fungal diseases and no sign of insect damage, chances are the tree is fine.

Other signs of a normal seasonal process: if the yellowing is taking place toward the middle of the branch and in a somewhat random pattern over the entire tree, and if other white pines in the area are showing the same symptoms.

Also inspect the bark for visible signs of insect damage, especially looking for small holes in the bark, which could be signs of several troublesome pests that bore holes into wood. Larger holes like these are seldom cause for alarm even if sap oozes out. These holes are most often made by a bird called the yellow-bellied sapsucker. And while the damage they do is unsightly, it rarely poses a real threat to the tree.

"So for those of you who have panicked momentarily from the sight of yellow needles on your white pines," James reassures, "I hope I've put your mind at ease, and I also hope you'll come to regard them as simply one more sign of the season."