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Ask the Gardener: Have hemlocks had their day in the Northeast?

In this Boston Globe article, George Barth from Hartney Greymont, a Davey company, talks about hemlock woolly adelgid, the damage it causes and what you should do.

Posted: July 8, 2021 hemlock woolly adelgid

Q. My husband and I have tried various remedies on our row of hemlock trees to eradicate the woolly adelgid to no real benefit. Do you have a tried-and-true application to suggest?

A. The threat from this tiny-but-deadly aphid relative from Asia, named for its small, gray, woolly balls of fluff that line the underside of hemlock branches, is increasing with our milder winters. Infected hemlocks can die in less than five years unless treated. Frankly, if you have a hemlock hedge, it makes sense to replace it with either a fence or a row of evergreen Arborvitae plicata, such as the Green Giant variety, which grows tall, narrow, and fast and is so bulletproof that deer won’t eat it. I would not plant more hemlocks because of their pest problems, which now include elongate hemlock scale, which is almost as deadly and common as woolly adelgid, according to George Barth, plant health care manager at Hartney Greymont, a Davey company, of Needham and Concord. “It produces orange-brown waxy spots that you can see through a magnifying glass on the underside of the needles.” Talk about a one-two punch!

To continue reading George's advice, click here

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