– Japanese walnut
Distribution: Occurring on both sides of the Cascades crest in Washington; southwestern British Columbia to the Columbia River Gorge in Washington, aslo in west-central Idaho.
Habitat: Riparian corridors, stream and river banks, thickets, and forest edge, at low elevations, often where distrubed.
Origin: Introduced from Japan
– black walnut
Distribution: In scattered locations across Washington, mostly east of the Cascades; central U.S. east to the Atlantic Coast.
Habitat: Disturbed areas and riparian zones, typically in the vicinity of urbanized areas where escaped from cultivation.