The quiet guardian of the eastern forest. Ancient. Irreplaceable. Disappearing. Tsuga canadensis, the Eastern Hemlock, is one of the most ecologically important trees in eastern North America and one of the most threatened. Its deep, year-round shade creates a unique microclimate along cold streams and northern hillsides that supports a community of organisms found nowhere else, including brook trout, Acadian flycatchers, and rare woodland plants that require the cool, humid conditions only mature hemlock creates. It is also one of the most graceful and beautiful native conifers, with soft, flat needles, delicate pendulous branches, and small elegant cones that give it a refined, feathery quality unlike any other evergreen. The woolly adelgid is killing millions of hemlocks across its range right now. Every tree grown in cultivation matters. If you are looking to buy Eastern Hemlock seeds or grow this native conifer from seed, you are doing something meaningful. One of the most ecologically important conifers in eastern North America, creating unique cold-stream microhabitats Exceptionally shade-tolerant, the only large native conifer that grows well in full shade Soft, flat needles with silvery undersides and small delicate cones, the most graceful of native conifers Critical habitat for brook trout, rare woodland plants, and the Acadian flycatcher Under severe threat from the woolly adelgid across its native range, every cultivated tree is a conservation act Things you probably did not know about the Eastern Hemlock It can live for over 500 years and be older than it looks. Eastern Hemlocks grow slowly in deep shade, adding annual rings so thin they are barely visible without magnification. Trees that appear modest in size may be centuries old. The oldest documented Eastern Hemlock in the Great Smoky Mountains was over 500 years old and not particularly large by hemlock standards. The shade it creates is unlike any other tree in the eastern forest. Mature Eastern Hemlock stands create the deepest, most consistent shade of any native hardwood or conifer in eastern North America. The understory of a hemlock grove can be as much as 97 percent shaded at midday, creating conditions so cool and moist that snow lingers weeks longer than in adjacent hardwood forest. This microclimate is why cold-water streams lined with hemlocks support brook trout populations that cannot survive in adjacent sun-exposed streams. It was the primary source of tannin for the American leather industry for over a century. The bark of Eastern Hemlock is extraordinarily high in tannins, the compounds used to convert raw animal hides into leather. From colonial times through the early 20th century, hemlock bark was stripped from trees across the Appalachians and Great Lakes region to supply tanneries. The tanning industry drove widespread hemlock logging and contributed significantly to the early deforestation of the Northeast. The woolly adelgid can kill a tree in 4 to 10 years. Adelges tsugae, an invasive insect from East Asia, arrived in the eastern United States in the 1950s and has since spread throughout the hemlock's range. The insect feeds on the tree's stored starches, eventually starving it. In the southern Appalachians, over 80 percent of hemlocks in some areas have been killed. Research into adelgid-resistant selections and biological control is ongoing, but the losses already sustained are irreversible on any human timescale. Growing Details Botanical Name: Tsuga canadensis Stratification: Required, 60 to 90 days cold stratification, surface sow as seeds need light to germinate USDA Zones: 3 to 7 Soil: Moist, well-drained, acidic, rich in organic matter, cool sites preferred Light: Full shade to full sun, the most shade-tolerant large conifer in eastern North America Height: 40 to 70 feet Spread: 25 to 35 feet Growth Rate: Slow, 6 to 12 inches per year Plant it in a cool, moist, shaded spot and let it become the quiet anchor of that corner of your property. It will outlive everything planted around it.
