Tsuga mertensiana

Mountain Hemlock
Pinaceae
Evergreen, Trees

TSUGA

These are mostly big, shallow-rooted trees with unusually graceful appearance. Horizontal to drooping branches bear needlelike leaves that are banded with white beneath, flattened and narrowed at the base to form distinct, short stalks. Small, oval brown cones hang down from branches. Deeply furrowed bark. Need some winter chill. Do best with acid soil, summer humidity, protection from hot sun and wind. Take well to heavy pruning; make excellent clipped hedges, screens. Easily damaged by salt and drought. In the Northwest, the hemlock woolly aphid can weaken these plants, especially those grown as hedges; it affects mainly T. heterophylla.

Tsuga mertensiana

To 50–90 ft. in the wild but is slow growing, smaller (20–30 ft. tall, half as wide) in gardens. Needles are 1/2–1 in. long, blue green with a silvery cast; grow all around stems to give branchlets a plump, tufty appearance. Trees at timberline frequently grow in horizontal or twisted fashion. Thrives on cool slopes with highly organic soil. Least adapted to lowland, hot-summer areas. Needs partial shade in Zone 14. Somewhat resistant to hemlock woolly aphid. Good for large rock gardens, containers, bonsai.