Alnus rubra Bong.
Red alder, Western alder
Betulaceae (Birch Family)
Synonym(s): Alnus oregona, Alnus oregona var. pinnatisecta
USDA Symbol: ALRU2
Graceful tree with straight trunk, pointed or rounded crown, and mottled, light gray to whitish, smooth bark. Alder roots, like those of legumes, often have swellings or root nodules containing nitrogen-fixing bacteria, which enrich the soil by converting nitrogen from the air into chemicals like fertilizers that the plants can use. The common name describes the reddish-brown inner bark and heartwood.
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Plant CharacteristicsDuration: Perennial
Leaf Retention: Deciduous
Leaf Arrangement: Alternate
Leaf Complexity: Simple
Leaf Shape: Elliptic , Ovate
Leaf Venation: Pinnate
Leaf Margin: Double-serrate
Breeding System: Flowers Unisexual , Monoecious
Size Notes: Height 20-40 feet, spread 20-30 feet.
Leaf: Dark green above.
Fruit: Conelike, 1/2 to 1 inch long.
Size Class: 12-36 ft. , 36-72 ft.
Bloom InformationBloom Color: Red , Green , Brown
Bloom Time: Mar , Apr
DistributionUSA: AK , CA , ID , OR , WA
Native Distribution: SE. Alaska southeast to central California; also local in N. Idaho; to 2500 (762 m).
Native Habitat: Moist soils including loam, gravel, sand, and clay, along streams and lower slopes; often in nearly pure stands.
Growing ConditionsWater Use: High
Light Requirement: Sun , Part Shade , Shade
Soil Moisture: Moist
CaCO3 Tolerance: Low
BenefitUse Food: Used in smoking meats and fish.
Use Other: Furniture, veneer, cabinets. Bark was used by Indians for dyes.
Interesting Foliage: yes
PropagationPropagation Material: Seeds , Softwood Cuttings
Seed Treatment: Best germination in full sun.
Maintenance: Can be shaped by pruning when young.
Find Seed or Plants
Find seed sources for this species at the Native Seed Network.
View propagation protocol from Native Plants Network.
National Wetland Indicator Status
From the National Organizations DirectoryAccording to the species list provided by Affiliate Organizations, this plant is on display at the following locations:
Native Seed Network - Corvallis, OR
BibliographyBibref 1149 - Alaska Trees And Shrubs (2007) Viereck, L. A. and Little, E. L.
Bibref 698 - Native Plants for Use in the California Landscape (1978) Labadie, E. L.
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Additional resourcesUSDA: Find Alnus rubra in USDA Plants
FNA: Find Alnus rubra in the Flora of North America (if available)
Google: Search Google for Alnus rubra
MetadataRecord Modified: 2009-01-29
Research By: TWC Staff