Alnus incana (L.) Moench
Gray Alder, Speckled Alder
Betulaceae (Birch Family)
USDA Symbol: ALIN2
Speckled alder is a tall shrub or small tree, 20-35 ft. tall, with multiple, crooked, leggy trunks. Bent in a wide curve at their base, the trunks become upright and picturesque. Deciduous leaves are rounded and coarsely toothed, remaining dark-green in autumn. The flower is a purplish-red catkin and the fruit is a woody cone.
This is the common alder throughout the Rockies.
From the Image Gallery
Plant CharacteristicsDuration: Perennial
Habit: Shrub , Tree
Leaf Retention: Deciduous
Leaf Arrangement: Alternate
Leaf Complexity: Simple
Leaf Shape: Elliptic , Ovate
Leaf Venation: Pinnate
Leaf Margin: Double-serrate
Leaf Apex: Acuminate , Acute , Obtuse
Leaf Base: Cuneate , Rounded
Breeding System: Flowers Unisexual , Monoecious
Fruit Type: Samara
Size Notes: Height to 25 M.
Bloom InformationBloom Color: Red , Green
Bloom Time: Mar , Apr , May
DistributionUSA: AK , AZ , CA , CO , CT , IA , ID , IL , IN , MA , MD , ME , MI , MN , MT , ND , NH , NJ , NM , NV , NY , OH , OR , PA , RI , UT , VA , VT , WA , WI , WV , WY
Canada: AB , BC , MB , NB , NL , NS , ON , PE , QC , SK
Native Distribution: Lab. to AK, s. to NJ, mts. of WV, n.e. IL, n.e. IA, MN, n.e. ND & w. mts. to NM & c. CA
Native Habitat: Wetlands & stream edges
Growing ConditionsWater Use: High
Light Requirement: Sun , Part Shade , Shade
Soil Moisture: Moist , Wet
Soil pH: Circumneutral (pH 6.8-7.2)
CaCO3 Tolerance: Low
Soil Description: Wet soils.
Conditions Comments: Alnus rugosa and Alnus tenuifolia are usually considered subspecies. Fast-growing and flood tolerant, this species is short-lived, rarely exceeding 40 years. It can be thicket-forming and provides erosion control along watercourses in the mountains. Alders fix nitrogen and thus serve as nutrient-giving pioneers in reclamation projects.
BenefitUse Wildlife: Songbirds, waterbirds, and mammals frequently use this species.
Use Other: The Navajo Indians made a red dye from the powdered bark.
Interesting Foliage: yes
PropagationDescription: Seeds of most alders germinate when they are fresh without pretreatment.
Seed Collection: Not Available
Seed Treatment: If seeds have dried in storage, a cool-moist stratification at 41 degrees for 180 days will be necessary.
Commercially Avail: yes
Find Seed or Plants
View propagation protocol from Native Plants Network.
Mr. Smarty Plants says
Alder native to Central Indiana
May 30, 2006
I am trying to find out whether there exists a plant named Alnus rugosa. I bought a plant recently that said Speckled Alder, Alnus serrulata (rugosa), but have been unable to determine if this is a c...
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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:
Natural Biodiversity - Johnstown, PA
Additional resourcesUSDA: Find Alnus incana in USDA Plants
FNA: Find Alnus incana in the Flora of North America (if available)
Google: Search Google for Alnus incana
MetadataRecord Modified: 2021-03-30
Research By: TWC Staff