Western Hemlock

Western hemlock (Tsuga heterophylla) is the dominant conifer of Pacific Northwest coastal rainforests and the state tree of Washington. It grows to 70 m or more in the wild, identified by a drooping terminal leader and needles that vary noticeably in length along the same shoot. In home landscapes it functions as a large specimen, windbreak, or dense evergreen screen, tolerating more shade than almost any other conifer in its range.

It requires cool, consistently moist conditions and acidic, humus-rich soil. Highly shade-tolerant, it germinates and establishes readily under a closed canopy and frequently colonizes nurse logs in nature. Poorly drained or drought-prone sites cause rapid decline. A deep wood-chip mulch layer helps retain soil moisture and moderate root-zone temperature. In zones 6–8b it is reliably cold-hardy but shows visible stress during prolonged summer drought.

Indigenous peoples of the Pacific Northwest ate the inner bark (cambium) fresh in spring or dried it into cakes. The bark's exceptional tannin content made this species a major commercial source of vegetable tannin for the leather industry into the early twentieth century; bark tannin was also applied externally for wound healing and skin ailments.