Origin: Eastern North America (native in Ontario)
Eastern hemlock is a large conifer. The tip of the tree (called the leader) is typically curved over.Read more about Tree, Bark, Twigs
Leaves are short flattened needles, mostly arranged in 2 rows on either side of the twigs.Read more about Leaves
Pollen cones are tiny and yellowish.Read more about Pollen cones
Seed cones are small and woody when mature.Read more about Seed cones
Eastern hemlock is a large conifer, up to 30 m (98') tall and 100 cm (3' 3") in diameter, with a conical crown.
Leaves are short, dark green, flattened needles, 1 - 2 cm (1/2" - 3/4") long, most appearing to be borne in 2 rows on either side of the twig and some, with underside facing up, on the top of the twig.
The underside of the needle has a dense row of white dots on either side of the mid-rib, which look like stripes.
New needles emerging at the tips of branches in the spring are a lighter green than needles from the previous growing season.
Seed cones open in September and shed their seeds in fall and winter. They may remain on the tree for a year after shedding seeds.
DistributionEastern hemlock's natural range extends east west from Nova Scotia to Minnesota and Missouri, and south to Georgia and Alabama. Of the eight species of hemlock (Tsuga spp) in the world, eastern hemlock is the only one native to eastern Canada.
Eastern hemlock is the state tree of Pennsylvania.
Examinations of pre-historic pollen records indicate that there was a massive decline in the abundance of eastern hemlock about 5,000 years ago. The reason for this decline has not yet been determined, although one theory suggests that it was caused by a large-scale pest outbreak.
The dense foliage in a stand of hemlocks creates an environment that is cooler, moister and darker than the surrounding forest. As the evergreen needles fall the soil becomes more acidic. Under these conditions few if any species can compete so the hemlock regenerates and grows as pure stands which can live for 600 years or, in some cases, as much as 1,000 years.
During the 19th century, eastern hemlocks were prized for their tannin-rich bark, which was harvested for use in the leather tanning industry. The bark had so much more value than the wood that trees were simply cut down, stripped of their bark, and left to rot on the forest floor in the same way that fins are cut from sharks or horns from rhinoseroses.
The wood of eastern hemlock is brittle and easily split. It is used in some construction, but the hard knots can dull saw blades and deflect nails.
In winter, eastern hemlock stands provide shelter for deer by trapping snow in the canopy and creating open ground below. These spaces are referred to as deer yards. The low-hanging branches are browsed by the deer. The oil-rich seeds also provide food for wildlife including porcupines, wild turkeys, ruffed grouse and many types of songbirds.
Eastern hemlock's place in Toronto's urban forest
Eastern hemlock stands still dominate the north facing slopes of Torontos ravines and river valleys.
Landscape value and potential for home planting
Eastern hemlock should be planted in sheltered, cool sites with moist, well-drained, acidic soils which mimic its natural habitat. It tolerates shade but is highly intolerant of drought, salt and pollution. Trees suffering from drought stress have scorched leaves and dying branches. Extended dry periods may kill entire trees.
Numerous cultivated varieties of eastern hemlock have been bred for a range of forms, growth habits, and leaf colours.
Pests and diseases: There are numerous pests and diseases affecting eastern hemlock, predominantly gypsy moth (Lymantria dispar) and spruce budworm (Choristoneura fumiferana). (For more information, see: Natural Resources Canada factsheet). Woolly adelgid (Adelges tsugae) is an insect pest that was accidentally introduced to North America, in Virginia, in 1951. Woolly adelgid infestations have severely impacted eastern hemlock populations in the United States. Since its introduction there woolly adelgid has gradually expanded its range and may become a problem in the Great Lakes region very soon. Woolly adelgid infestations appear as wooly masses on the twigs or needles and result in loss of tree vigour, defoliation, and death.
This tree is available for planting through LEAF's backyard tree program.
Links to maps at Canadian Tree Tours: