Alnus
alder
5 species
3 subspecies and varieties
Show only taxa with photos
Order by:
Scientific name
Common name
Display as:
Alnus glutinosaBlack alder, European alder
Distribution: Occurring west of the Cascades crest in King County, where escaping from a wetland restoration planting. Great Lakes region east to the Atlantic Coast.
Habitat: Wetlands at low elevation.
Origin: Introduced from Europe
Flowers: March-May
Alnus incanamountain alder
Distribution: Occurring chiefly east of the Cascades crest in Washington; Alaska to California, east to the Rocky Mountains, northern Great Plains, and eastern North America,
Habitat: Moist places, streamsides, and avalanche chutes from low to middle elevations.
Origin: Native
Flowers: March-May
Growth Duration: perennial
ssp. tenuifolia – mountain alder
Alnus rhombifoliawhite alder
Distribution: Chiefly east of the Cascades crest in Washington; Washington to California and Nevada, east to Idaho.
Habitat: Near streams at low elevations.
Origin: Native
Flowers: January-April
Growth Duration: perennial
Alnus rubrared alder
Distribution: Occurring chiefly west of the Cascades crest in Washington; Alaska to California, disjunct to the east in northern Idaho.
Habitat: Moist areas at low elevations.
Origin: Native
Flowers: March-April
Growth Duration: perennial
Alnus viridisgreen alder, mountain alder
Distribution: Widely distributed throughout the mountainous areas on both sides of the Cascades crest in Washington; Alaska to California, east across the northern half of North America to the Atlantic Coast.
Habitat: Moist areas, low to high elevations.
Origin: Native
Flowers: May-July
Growth Duration: perennial
ssp. fruticosa – Siberian alder
ssp. sinuata – mountain alder, Sitka alder