Puget Lowland

The Puget Lowland is the glacial trough between the Cascades and the Olympics, covering Seattle, Tacoma, Everett, Olympia, and Bellingham. Winters are mild and wet, summers are genuinely dry, and the glacial soils drain fast, which catches out anyone assuming the Northwest is wet year round. Natives such as flowering currant, broadleaf stonecrop, and Oregon gumweed are built for that soaking winter and rainless summer, and they want no irrigation once established.

Conditions: Fast-draining glacial outwash and till, 30–50 inches of rain falling mostly October through April, mild winters, dry summers.

Cities and areas: Seattle, Tacoma, Everett, Olympia, Bellingham, Bremerton.