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Western Hemlock


Scientific Name:
Tsuga heterophylla

Other Common Names:
Pacific hemlock

Under Power Lines:
No—this tree is not approved for planting under power lines.

Street Tree Planting:
Yes—minimum planting strip width of 12 feet and at least 30 feet from intersections. If planting a street tree, you must be approved for a permit.

Washington’s state tree, the Western hemlock is a large handsome evergreen native with graceful down-sweeping branches and feathery foliage.


Mature Height:
90 feet

Mature Spread:
30 feet

Feathery, flat sprays of foliage are yellow-green on top and whitish underneath.

Small cones (about 2 cm long) and purplish-green when young.

Cultural Notes:
Can be grown in full sun to full shade and in fairly wet to dry site.  Prefers acidic, cool, moist to wet soils with good drainage.

Potential Problems:
Generally pest free.

Minimum Planting Distances:

  • 20 feet from house or building
  • 3 ½ feet back from the face of the curb
  • 5 feet from underground utility lines
  • 10 feet from power poles
  • 7 ½ feet from driveways (10 feet recommended)
  • 20 feet from street lights and other existing trees
  • 30 feet from street intersections

More Information:


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