Western Hemlock

Tsuga heterophylla

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

Power Line Approved: No

Min. street tree planting width: 12 feet

Mature Height: 80 feet

Mature Spread: 20 feet

Tree Shape: Pyramidal and pendulous

Where to Plant:
Works well in your yard. Give it room to develop. Great for greenspaces that are unimproved right of ways adjacent to your property. An unimproved right-of-way (ROW) is an area originally set aside for alleys, streets, or paths that has not been developed. If you want to plant this tree in an unimproved right of way, select the street tree option on your application so a City of Seattle arborist can inspect its location and approve a permit.

Feathery, flat sprays of foliage are green on top and whitish underneath. Needles are uneven in length.

Small cones (about 1” long) and purplish-green when young.

Preferred Site Conditions:
Can be grown in full sun to full shade.  Prefers moist but well drained soil.

Potential Problems:
Hemlock woolly adelgid. Western hemlock is not negatively affected by this insect.

Minimum Planting Distances:

  • 15 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

Additional Resources