Hemlock Infestation? Act NOW to Save Your Trees

Hemlock woolly adelgid in the Seattle area.

If you've seen little white spots on the tips of your Hemlock branches, your tree has the dreaded hemlock woolly adelgid (HWA) Adelges tsugae. 

This insect damages trees quickly and weakens hemlocks, so if you value your hemlocks, you should act to kill the HWA and prevent their spread to other hemlock trees.




Here are 6 steps you can take to protect your hemlocks from HWA and reduce infestation:

- remove dead and dying branches (this pruning can be done by Blooma Tree Experts);
- discourage birds and squirrels from visiting your hemlocks, since they spread HWA;
- during drought, water your Hemlock roots at dripline, slowly, 1" per week;
- do NOT apply nitrogen fertilizer during infestation; after the insects are under control, apply fertilizer;
- direct a water spray to the eggs to help dislodge them; and/or
- apply a pesticide (see the next section).

The "woolly" evidence of HWA infestation

What about pesticides?
According to the US Forest Service, if you want to save an eastern hemlock, you must use chemicals. However, you must be committed to treating your trees for several years--until all trees in the vicinity infested with HWA are dead. You may want to consider the cost and effort of that compared to removing your tree now. You might want to just save a particular hemlock tree or trees that you value.

There are two methods of applying insecticide:
1) thoroughly drench infested trees with horticultural oil, insecticidal soap, or any one of several petrochemical insecticides (this usually is best done by a professional); or
2) in April to May, inject a systemic insecticide, such as imidacloprid or acephate, into the roots of infested hemlocks with a hydraulic injection needle. This works on healthy hemlocks only; if the tree is in decline, the first method will work best. (Call Martin at Blooma for a referral in the Seattle area: 206-714-9835)

A healthy hemlock is a beautiful tree.

An excellent, thorough article about HWA can be found here: http://na.fs.fed.us/fhp/hwa/control/mcclure.pdf

If you live in the Seattle, WA area and need a professional pruning or removal of a hemlock tree, please call Blooma Tree Experts for a free quote: 

(206) 714-9835.