Eastern hemlock (Tsuga canadensis) has been described as the most graceful of the evergreen trees. Native to Canada and the eastern United States, hemlock usually grows 40 to 70 feet in height, sometimes to over 100 feet. Hemlock’s shape is softly pyramidal, with a strong, tapering trunk and branches that become more pendulous and feathery with age.
Needles are soft, about ¾ of an inch long, dark green above and with whitish bands beneath. Cones are a dainty ¾ inch long, light to medium brown, usually growing high in the tree and hanging like little ornaments.
Hemlock is one of the few evergreen trees that tolerate shade, which enables them to thrive on north-facing slopes where other evergreens cannot. They also do fine on rocky ridges, including in our Middlesex Fells. They don’t like drought or wind, however. Hemlocks can also tolerate shearing and pruning, and have been used to create spectacular screens and hedges.
Unfortunately, hemlocks in our forests and our landscapes have been the victims of an invasive pest called hemlock woolly adelgid. Woolly adelgid is a sucking insect, similar to aphids, whose tell-tale sign is its egg sacs, which are tiny, cottony balls of fluff that appear on the underside of the needles. Infested trees often die within a few years, or are so weakened that they eventually succumb to other diseases or pests. Current treatment for woolly adelgid is spraying with horticultural oil, which suffocates the eggs, but this practice is difficult and often expensive. The scientific community continues to seek out alternate solutions for fighting this destructive pest.
A lovely hemlock graces the landscape near the main entry of Oak Grove Cemetery. Its strong central trunk and outstretched branches reflect the form and inspiration of the magnificent World War II memorial statue, “The Angel of Victory and Peace”.
– Submitted by Aggie Tuden, Medford Tree Warden