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Home > Landscaping > Native Plants for Western Washington Gardens and Restoration Projects



Alnus rubra

Red Alder

Flowering Period: Mar March
Flower color: red Flower color: green Flower color: brown
Mostly sunny
Moist soil


At a Glance: A fast-growing deciduous tree well suited to disturbed sites.

Height: Up to 80 feet (25 meters).
Growth Form: Tree.
Stems: Bark is thin and gray with smooth white patches of lichens.
Leaves: Leaves are alternate, broadly elliptic, sharply pointed at the base and tip, smooth above and slightly rust-colored below. Leaf margins are wavy and folded-over with coarse, blunt teeth. Size: 5-15 cm (2-6 in) long. Leaves remain green until dropping in the fall.
Flowers: Male flowers appear as hanging, cylindrical spikes (catkins) and emerge before leaves while female flowers are borne in small stubby cones. the catkins are reddish-orange with yellow highlights, 5-12 cm (2-4.5 in) long. The femal cones are green when young, then turning brown, 2 cm long.
Flowering Period: March.
Fruits: Clusters of brown cones 2 cm long containing oval-shaped, winged seeds remain on the tree over winter months.

Alnus rubra
Photo © 2004, Starflower Foundation
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Sun/Shade Tolerance Hydrology Elevation Range
Shade intolerant.

full sun > 80%
mostly sunny 60%-80%
partial sun and shade 40%- 60%
mostly shady 60%-80%
full shade > 80%

Grows taller in drier conditions.

wet
moist
dry

Wetland Indicator Status:
Below about 300 meters elevation.

low elevation
mid elevation
sub-alpine
high elevation


Soil Preferences
Fixes nitrogen, can flourish in poor soils.
sandy soils
gravelly soils
clay soils
muddy soils
peaty soils
well drained soils
shallow soils
deep soils
acidic soils
basic soils
humic soils
nutrient rich soils
nutrient poor soils
mineral soils
organic soils

Habitat Preferences
Aquatic and Wetland:
Ponds or lakes
Shallow pools
Sloughs
Swales or wet ditches
Seasonally inundated areas
Marshes or swamps
Aquatic bed wetlands
Emergent wetlands
Scrub-shrub wetlands
Forested wetlands
Bogs, fens
Seeps, springs
Shorelines and Riparian:
Lake shores
Bog margins
Streams or rivers
Stream or river banks
Riparian corridors
River bars
Floodplains
Bottomlands
Alluvial areas
Saltwater Areas:
In or near saltwater
Mud flats
Tidal areas
Estuaries
Saltmarshes
Brackish water
Seashores
Coastal dunes or beaches
Rocky or Gravelly Areas:
Coastal bluffs
Cliffs
Rocky slopes
Outcrops
Crevices
Glacial outwash
Gullies
Slide areas
Sub-alpine and Alpine:
Heaths
Snow beds
Tundra
Avalanche tracks
Forests and Thickets:
Forests and woods
Open forests
Coniferous forests
Old growth forests
Deciduous forests
Mixed forests
Nurse logs
Forest edges, openings, or clearings
Thickets
Meadows and Fields:
Pastures or fields
Meadows or grassy areas
Mossy areas
Disturbed Areas:
Roadsides
Trailsides
Logged sites
Burned areas
Disturbed sites

Wildlife Value
Berries
Seeds
Nectar for hummingbirds
Nectar for butterflies
Host for insect larvae
Thickets and shelter
Thorny or protective cover

Birds: Birds that eat the seeds, buds, and insects associated with red alder include mallards, widgeons, grouse, bushtits, kinglets, siskins, vireos, warblers, and chickadees. Birds that use red alder for cover and nesting include warblers, bushtits, and sparrows. Cavity-nesting birds nest and roost in the red alder tree cavities.
Insects: The leaves are eaten by swallowtail butterfly larvae and tent caterpillars.
Mammals: Mammals that eat the twigs, leaves, or wood include snowshoe hares, beavers, porcupines, deer, and elk.
Other Wildlife: Alders create organic debris for soil organisms. Additionally, alders create good riparian cover for fish.


Ethnobotanical Uses and Other Facts
(data not available)


Suggested References



The landscaping and restoration information provided on this page is taken from the Starflower Foundation Image Herbarium. All photographs © Starflower Foundation unless otherwise noted.