Black Hemlock

Tsuga mertensiana (SU-ga mer-TEN-si-a-na)

Family: Pinaceae Unknown Canopy (>40 ft)

Mountain hemlock is a medium-sized, needled, coniferous, evergreen tree in the pine family (Pinaceae). It is native to the southeastern coasts of Alaska and British Columbia, the mountains of Washington and Oregon and the high Sierras of California and Nevada. The genus name, Tsuga, originated from the Japanese word "tsu-ga," which means "tree" and "mother." The species name, mertensiana, is named in honor of German botanist Franz Karl Mertens. The mountain hemlock prefers full sun and moist, cool summers. It is less tolerant to shade than the western hemlock. It does not perform well in the southeastern United States due to heat intolerance. This tree does best in areas where the growing season is short and the winters are cold and long. When the mountain hemlock is young, it may be pruned as a hedge. A mature tree reaches a height of 30 to 100 feet with a width of 10 to 15 feet. The tree may be propagated by seedlings, cuttings and layering. It has a conical or pyramidal crown, dense foliage, spreading branches, and the leading shoot may be tilted. The trunks of the tree are flexible and can withstand the weight of snow for months. After the snow melts, the trees will upright themselves. The tallest known trees have reached 175 feet, and the oldest trees are 500 to 1400 years old. Use mountain hemlock in containers, a recreational play area or in a woodland landscape. It is great in a rock or winter garden. It can be used as a hedge for screening and privacy, and as a specimen tree. Quick ID Hints : The branches turn upward at the tips. The needles are of equal length, dense on all sides of the stems in a bottle brush effect. The cones are narrow and long, measuring about 3 inches long and 1 inch wide. The seed cones are purple and then ripen to a grayish-brown. Insects, Diseases and Other Plant Problems: The mountain hemlock has no serious disease problems. Potential pests include spruce spider mites and hemlock wooly adelgid. VIDEO created by Ryan Contreras for “Landscape Plant Materials I: Deciduous Hardwoods and Conifers or Landscape Plant Materials 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, 56 attributes.