Introduction to the Eastern Hemlock:

Eastern hemlock (Tsuga canadensis), also called Canada hemlock or hemlock spruce, is a slow-growing long-lived tree which unlike many conifers grows well in shade. Hemlock may take 250 to 300 years to reach maturity and may live for 800 years or more. Eastern hemlock has a nodding" form defined by it's limbs and leaders and can be recognized at great distances. Some rank this tree among the "quality plants" to add to the landscape.

Unlike most conifers, eastern hemlock has to have shade provided by hardwoods to regenerate. Unfortunately, stands of these trees are being damaged by the hemlock wooly adelgid.

The Northeastern Eastern Hemlock Range:

Eastern hemlock covers the entire U.S. Northeast extending into Canada and to the west. The northwestern limit of eastern hemlock extends to Minnesota, through Wisconsin, northern Michigan and into Ontario, southern Quebec, New Brunswick and all of Nova Scotia. Eastern Hemlock then drops down and through the Appalachian Mountains southward into northern Georgia and Alabama.

The Beautiful Eastern Hemlock:

Canadian or Eastern hemlock may be one of the most beautiful conifers in North America. Due to hemlocks being a particularly long-lived tree, several very large or otherwise impressive trees exist up and down the east coast of North America and all trees are impressive in the landscape. Hemlock, with its soft green needles attached to gently arching branches, often reaching to the ground, look their best with lower branches left on and touching the ground.

They are "long-lived, refined in character and have no off-season" according to Guy Sternberg in Native Trees in North American Landscapes.

Identification of Eastern Hemlock:

The evergreen Eastern hemlock is a medium to large tree that can often grow beyond 70 feet in height. The eastern hemlock "crown" tends to be weeping and pyramidal and limb sprays usually grow down to the ground. Two-ranked needles grow along a stem, are usually flattened and blunt, silvery under the needle and less than an inch long. Hemlock cones are small and less than a half inch long.

The Beneficial Eastern Hemlock:

Lumber production from eastern hemlock reached its peak between 1890 and 1910 but is seldom harvested for solid wood products now. Much of the present harvest production is used in pulping and newsprint. Eastern hemlock often is planted as an ornamental because of its good foliage color, and adaptability to pruning. Some effort is being made to plant the species under forest conditions because it is so important to wildlife.

The Damaging Hemlock Wooley Adelgid:

The eastern and Carolina hemlock is now being decimated by the hemlock wooley adelgid (HWA) or Adelges tsugae. Adelgids are small, soft bodied aphids that feed exclusively on coniferous plants using piercing-sucking mouth parts. They are an invasive insect and thought to be of Asian origin.

The cottony-covered insect hides in its own fluffy secretions and can only live on hemlock. The hemlock wooley adelgid was first found on ornamental eastern hemlock in 1954. HWA became a pest of concern in the late 1980s as it spread into natural stands. It now threatens the entire hemlock population of the eastern United States.