Native Plant of the Month: Western hemlock

Western Hemlock – Tsuga heterophylla
In 1947 the western hemlock, or Tsuga heterophylla, was selected as the official state tree of Washington because of the significant role it played in Washington’s forest industry. The western hemlock is one the many evergreen trees found in Washington’s forests. Vast evergreen forests have also inspired Washington’s unofficial nickname, “The Evergreen State”. 

The western hemlock is the largest species of hemlock with an average height between 90 and 200 feet and a trunk diameter that can reach up to 9 feet! This tree has flat and short needles that are unequal in length, ranging between 5 to 20 millimeters long. The cones are small, about 2cm long, and light brown in color. The bark is reddish brown, rough and scaly. Over time, the bark of older trees becomes very thick and furrowed.  
In Washington, western hemlocks extend from the west coast to the Cascades, but do not grow east of the Cascades. They grow on many different types of soil and on decaying wood. Young western hemlock trees flourish under the forest canopy because the species thrives in both full sunlight and shade. 

If you’ve spent any time in Western Washington, you’ve probably seen many western hemlock trees. One of the easiest ways to identify this iconic tree is by the way it “hangs its head”, most western hemlocks have a droopy top because the terminal ends of the tree fall to one side unlike other evergreen trees which come to a straight point.  

Want to learn more?
USDA Facts Sheet