Pacific Hemlock

Tsuga heterophylla (SU-ga het-er-oh-FIL-uh)

Family: Pinaceae Unknown Canopy (>40 ft)

Western hemlock is a large, fine-textured needled evergreen coniferous tree in the pine family (Pinaceae). It is the state tree of Washington. It is native to southern Alaska and down to the west coast of northern California. It is also found in the Rocky Mountains of southeastern British Columbia, northern Idaho, and southwestern Montana. The genus name, Tsuga , originated from the Japanese word that means "mother" and "tree." The species name, heteros , is Greek for "different” and phyllon for “leaf,” which refers to the variable length of the western hemlock needles. Western hemlock prefers full sun but is tolerant of partial shade to full shade. It grows well in acidic soils and needs moist to wet soils with good drainage and is intolerant to drought. This tree prefers coastal and mid-mountain forests. In the presence of the full sun, grows much faster. Seedlings typically grow on decaying wood and grow slowly in shade. The western hemlock may also germinate on the surface of the soil and requires cold stratification. Propagation by layering and cuttings have also been reported. A mature tree can reach a height of 60 to 240 feet and a width of 12 to 40 feet. Reportedly, the tallest western hemlock is over 240 feet tall, and some of the trees are over 1200 years old. The trunk of the tree has been known to reach up to 9 feet in diameter. Western hemlock is primarily used for making lumber for building. It is the best source of pulpwood for use in paper production and is also used to make cellophane. Native Americans used the timber for firewood or making poles. They also used the bark to make dye or paint, and they used the pitch as a cosmetic. Consider the western hemlock in a woodland garden as a specimen, hedge or screen. It has also been used in bonsai.The western hemlock is a favorite habitat for many birds. The seeds from the cones are a food source for chickadees, pine siskins, and deer mice. Some small mammals nibble on the bark, and deer and elk browse and enjoy the foliage. The western hemlock may be confused with the eastern hemlock (Tsuga canadensis). The distinction is made by comparing the needles' size and arrangement, the size of the bands on the undersides of the needles, and the shape of the buds. Quick ID Hints: Bark is grayish-brown, scaly, and fissured. Foliage is finely textured and fern-like and droops at the ends. Flat needles, spirally arranged with different sizes alternating on the same stem. Lower surface of the needle has two white broad bands and unclear green margins. Buds are spherical. Small woody cones appear in August. Insects, Diseases and Other Plant Problems: Hemlock wooly adelgids may be found on the foliage and suck the sap from the tree. They appear as small white nodes on the underside of the branches. Defoliating insects such as the larvae from caterpillars may kill the tree if the damage is severe. These insects include hemlock looper larvae, silver-spotted tiger moth larvae and hemlock sawfly larvae. Hemlock rust mite and elongate hemlock scale are also a concern. Parasites such as hemlock dwarf mistletoe can rob the tree of nutrients. Bracket fungi or conks cause the wood to decay. Porcupines are known to gnaw on the bark. The tree has a shallow root system and can be prone to wind damage VIDEO created by Ryan Contreras for “Landscape Plant Materials I: Deciduous Hardwoods and Conifers or Landscape Plant Materials and II: Spring Flowering Trees and Shrubs,” a plant identification course offered by the Department of Horticulture at Oregon State University .

Source: NC State Extension Gardener Plant Toolbox ↗ NC State Extension Gardener Plant Toolbox, 57 attributes.