Tsuga heterophylla aka Western Hemlock Spruce

Tsuga heterophylla, or western hemlock, is an evergreen conifer in the pine family. Its native range runs from southern Alaska to northern California. It also grows inland in British Columbia, Idaho, and Montana. It is Washington's state tree and grows in moist forests. Seedlings can take root on old logs and rotting stumps. Their roots need a damp surface to keep growing.

In gardens, trees reach about 60–100 feet (18–30 m) tall. Some reach 150 feet (46 m), while forest giants exceed 240 feet (73 m). Reported widths range from 12–40 feet (3.7–12.2 m). Young trees have a narrow, cone-shaped crown with drooping branch tips. Soft, flat needles vary in length along each twig. New needles start bright green, then turn dark green. Two broad white bands mark their lower sides. The thin twigs bend easily and bear fine hairs. Young bark is dark and scaly. Older bark turns gray-brown and forms cracks and flat ridges.

Each tree bears both male and female cones in spring. The small yellow male cones grow on last year's shoots. Purple female cones form at the twig tips. These become light brown seed cones about an inch long. Each cone holds about 30–40 small seeds. Cones mature in August, and seeds ripen by late September. The cones open in October to shed their seeds. Birds nest in the tree and eat its seeds. Small mammals eat the bark, while deer and elk browse shoots.

Western hemlock grows in sun, partial shade, or full shade. Sun helps it grow faster; shade slows young trees. It needs moist soil with good drainage and cannot tolerate drought. NCSU favors acidic soil, while RHS lists a wider pH range. RHS also lists clay, loam, sand, and chalk soils. Protect the tree from wind because its roots are shallow. NCSU lists USDA zones 5–8; RHS gives a UK rating of H6. The tree needs little routine pruning. Large woodland gardens can use it as a specimen, screen, or hedge. Growers also train it as bonsai.

Its wood supplies lumber and paper pulp. Bark has supplied dye and tannin. RHS reports few pest or disease issues, but NCSU lists several threats. These include woolly adelgids, mites, scale, and insects that strip needles. Dwarf mistletoe draws nutrients, and fungi can rot the wood. PFAF records edible inner bark and shoots, though its food rating is low. Pitch has served as chewing gum, and leaf oil flavors foods. PFAF reports no known hazards, rather than proven safety. It also records past medicinal uses of bark and twigs.