Western Hemlock

Western hemlock (Tsuga heterophylla)
Tsuga heterophylla

Tsuga heterophylla, commonly known as the Western Hemlock, is the largest species of hemlock growing to 200′ tall, and with a trunk diameter of up to 4′. The tallest specimen, 78.9 m tall, is in Prairie Creek Redwoods State Park, California. It is long-lived, with trees over 1200 years old known.

Western hemlock bark is thin, furrowed, and brown. Young trees have a broad conic shape with a strongly drooping lead shoot. At all ages, it is readily distinguished by the pendulous branchlet tips. The needles are short, averaging less than 1″ long, strongly flattened in cross-section, mid to dark green above, and with two broad bands of white stomata below with only a narrow green midrib between the bands.

The cones are small, pendulous, slender, and cylindrical, 1-3″ long with thin, flexible scales. The immature cones are green, maturing gray-brown 5-7 months after pollination. It is a very shade-tolerant tree, with young plants typically growing up under the canopy of other conifers such as Sitka Spruce and Douglas-fir. Without disturbance, hemlocks eventually dominate the canpoy, as other conifers cannot grow in their dense shade. However, storms and (rarely) wildfires create openings in the forest where less shade-tolerant species can regenerate.

Western Hemlock is the state tree of Washington.

Cultivation & Uses

Western Hemlock is cultivated in its native territories, where its best reliability is seen in wetter regions.

Western Hemlock boughs are used to collect herring eggs during the spring spawn in southeast Alaska. The boughs provide an easily collectible surface for the eggs to attach to as well as provide a distinctive flavor. This practice originates from traditional gathering methods of the Tlingit people.

The edible cambium can be collected by scraping slabs of removed bark. The resulting shavings can be eaten immediately, or can be dried and pressed into cakes for preservation. The bark also serves as a source of tannin for tanning.

Western Hemlock is also an important timber and paper tree, and is grown worldwide as an ornamental species.

  • Light Requirements: Full Sun, Part Shade, Full Shade
  • Water Requirements: Dry, Moist
  • Ease of Growing: Easy to grow
  • Growth Rate: Fast
  • Spreads: No
  • Wildlife Support: Pest-eating Insects, Birds or Mammals
  • Edible: No
  • Mature Height: 120-200
  • Mature Width: 30-40ft