Tsuga mertensiana Pinaceae
Mountain Hemlock tsoo-GA mer-TEN-si-a-na
- Conifer, evergreen tree, 30-100 ft (9-30 m), narrowly conical, branches and twigs thin and nodding; bard
charcoal gray to reddish brown, scaly and deeply fissured.
Needles (leaves) arranged radially around the stem, but densest on the upper side, linear, 10-20 mm long,
stomatal lines on both sides, apex blunt, base attached to the stem via a roundish "peg" and short petiole,
gray-green to silver-white; on short lateral branches the needles are grouped in star-like clusters.
Cones oblong-cylindrical, stalkless, 5-8 cm long, pendulous, often purple when young.
- Sun, if soil not too dry. Best growth occurs in areas of moist air and cool summer temperatures. Some landscapers suggest when planting in lowland
gardens in the Pacific Northwest to plant the tree high and backfill with gravel and organic matter mixed with clay. It does not usually perform well in eastern states.
- Hardy to USDA Zone 5 Native to southern Alaska along the Pacific coast to
British Columbia and in mountains to central California, also southeast of B.C. in Rocky Mountains of
northern Montana, Idaho. In contrast to Western Hemlock (Tsuga heterophylla), Mountain
Hemlock mostly grows at high altitudes except in the far north, from sea level to 1000 m (~3,300 ft) in
Alaska, 1400–2400 m (~4,500-8,000 ft) in the Cascades in Oregon, and 2500–3050 m (~8,200-10,000 ft) in the
Sierra Nevada. On windy, alpine slopes it may occur in "krummholz form" (from German:
krumm, "crooked, bent, twisted"; and holz, "wood").
- A few cultivars available, including the spreading
- mertensiana: after Karl Heinrich Mertens, a German botanist who discovered it in 1827.
- Oregon State Univ. campus: several trees southeast of Peavy.