Hemlock tree dying

Asked April 6, 2016, 9:02 PM EDT

We have 8 hemlock trees, one is dying (dead). Any suggestions on what might be the cause. What should we do to prevent damage to the others?

Allegheny County Pennsylvania

1 Response

Without any description of symptoms, it is hard to say what exactly may have caused the one hemlock tree to die. There are some diseases that affect hemlock trees that may cause death after a number of years of decline. More information on these diseases can be found here: http://extension.psu.edu/pests/plant-diseases/all-fact-sheets/hemlock-diseases . There are also two insect pests that have been causing problems for hemlocks in Pennsylvania. One is hemlock woolly adelgid and the other is elongate hemlock scale. The presence of white cottony or fuzzy masses on the needles would indicate one or the other of these two insect pests. More information on these two insects can be found here:
hemlock woolly adelgid: http://ento.psu.edu/extension/factsheets/hemlock-woolly-adelgid
elongate hemlock scale: http://ento.psu.edu/extension/factsheets/elongate-hemlock-scale
If you can provide more details on what symptoms you have
observed in the dying hemlock, we may be able to more specifically diagnose the problem. Once the problem is diagnosed, then steps to protect your other hemlocks can be determined.