Previously treated hemlock showing beautiful new growth at the branch tips this spring

This time of year, healthy hemlocks are looking bright and shiny. While our hemlock treatment program is wrapping up for the season, evidence of past treatments is appearing on trees that were in rough shape a couple years ago.

Look around the woods right now and you might see hemlocks putting on new bright green and tender needles at the tips of the branches. Healthy new growth is a great sign that hemlocks are persisting and recovering from hemlock woolly adelgid (HWA) infestation.

If you have hemlocks that were first treated in the last few years, you may be seeing this new growth for the first time in a while.  It’s very exciting to see this bright new growth on trees that have suffered from HWA because this is a good sign that your trees have responded to treatment and are recovering from the stress of HWA.  Alternatively, if you have infested trees that haven’t been treated yet, but are still putting on new growth, this is a good sign that those trees may be able to respond well to treatment.

The results of hemlock treatment are not instantaneous. It can take several months for chemical protection to take full effect in a tree’s system, and it might be a couple years before a treated tree will start putting on new growth. However, if you are not seeing new growth within two or three years of treatment, then that could be an indication of a different problem besides HWA.

If you have declining hemlocks and want to learn more about how to protect them from HWA, please see our Info for Landowners page.