Fresh snow piles and hemlock trees on a December morning at The Boulders in Dalton. Photo by Thom Smith

The friendly hemlock — East coast evergreen

Berkshire Naturalist Thom Smith finds color in the winter woods. Never confuse this evergreen with a Christmas Tree — regardless of the name, it will be a happier tree outside than inside, as its needles fall upon drying out. It’s a common tree in cool woods with moist soil throughout New England, and north well into Canada, giving it the common name Canadian hemlock. In French-speaking Quebec, it goes by “Pruche du Canada.” Here in New England, we know it by the name eastern hemlock or hemlock spruce. 

Just don’t confuse it with the hemlock that killed Socrates; it isn’t poisonous and is an age-old remedy for many ailments besides making a tasty tea rich in Vitamin C.  Native Americans had about a dozen illnesses they would treat with this elixir, including colds, coughs, and fever. They may not have identified scurvy as a disease resulting from a lack of vitamin C (ascorbic acid), but they knew hemlock tea and concoctions from about six other evergreens would relieve it and its many symptoms.  

They and early colonists also used hemlock bark for dyes, and its cambium or inner bark for soups and bread, and mixed with it with animal fat and dried fruit. 

Today we chip and shred its bark for garden mulch and unromantically manufacture its lumber into pallets, structural lumber, and pulpwood. 

Hemlock is slow to mature and is known to last more than 300 years and reach heights of 70 or more feet. In our woods, we often see its seedlings, a few inches tall, thriving under the cool shade of its parent trees. Under cultivation, it grows well in full sun or shade, provided the soil is moist with good drainage. 

Hemlock needles are short, about ½ inch long, and flat with two whiteish or light blueish lengthwise strips beneath. When crushed their odor is said to resemble somewhat that of the poison hemlock (Conium maculatum) that was introduced from Europe though uncommon in The Berkshires.  

Hemlock cones are small, averaging about ¾ inches, and ripen in the fall, ready for a variety of wildlife including our state bird, the black-capped-chickadee, and the dark-eyed junco, American goldfinch, erratic pine siskin and evening grosbeaks, among others. 

Deer are known to hole up under hemlock stands in times of heavy snow, and while it may be a second choice, they will feed on it when convenient. Porcupines and other woodland rodents seek winter nutrition in stands native trees.

Its nemeses are wind and the woolly adelgid. In the last 20 years, the hemlock woolly adelgid, an aphid-like insect native to Japan and China, has moved through the East Coast and inland, increasing its range by about 10 miles each year, and has devastated many hemlock populations in the Eastern U.S. 

The use of chemical injections and biocontrol treatments helps, although unfortunately, the aphid-like insect may win this battle, especially in vast stands of hemlock forests.

Cold winters slow the insects and protects the trees, and though they have vanished in much of Connecticut, they still grow in the Berkshires for now, from Bartholomew’s Cobble and Wahconah Falls to the upper slopes of Mount Greylock. 

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