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Betula occidentalis Hook.
Water Birch, Mountain Birch
Betulaceae (Birch Family)
Synonym(s): Betula beeniana, Betula fontinalis, Betula occidentalis var. inopina, Betula papyrifera ssp. occidentalis, Betula papyrifera var. occidentalis
USDA Symbol: BEOC2
USDA Native Status: L48 (N), AK (N), CAN (N)
Water birch or mountain birch is a 20-30 ft., multi-trunked tree with shiny, reddish-brown bark. Its delicate, graceful appearance is created by slender, spreading, pendulous branches. Shrub or small tree with rounded crown of spreading and drooping branches, usually forming clumps and often in thickets. The red color of the branches and twigs creates the same winter effect as red-twigged dogwoods. The small, deciduous leaves are bright green above and yellow-green beneath becoming bright yellow in fall.
This uncommon but widespread species is the only native birch in the Southwest and the southern Rocky Mountains. Sheep and goats browse the foliage.
From the Image Gallery
Plant CharacteristicsDuration: Perennial
Leaf Retention: Deciduous
Leaf Arrangement: Alternate
Leaf Complexity: Simple
Leaf Venation: Pinnate
Breeding System: Flowers Unisexual , Monoecious
Fruit Type: Samara
Size Notes: Up to about 30 feet tall.
Bloom InformationBloom Color: Yellow , Green , Brown
Bloom Time: Apr , May
DistributionUSA: AK , AZ , CA , CO , ID , MT , ND , NE , NM , NV , OR , SD , UT , WA , WY
Canada: AB , BC , MB , NS , NT , ON , SK , YT
Native Distribution: AK, e. of the Cascades to CA, e. to s. Man., the Dakotas & n. NM
Native Habitat: Wooded, mt. ravines; stream banks; bottomlands
Growing ConditionsWater Use: High
Light Requirement: Sun , Part Shade , Shade
Soil Moisture: Moist
CaCO3 Tolerance: Low
Soil Description: Moist soils.
Conditions Comments: Do not prune until summer when the sap has stopped flowing. Susceptible to borers, aphids, and other problems when grown in dry soil. Does not cast heavy shade, permitting underplanting.
PropagationDescription: Sow seed as soon as ripe. Germination is facilitated by exposure to light; never plant too deeply.
Seed Collection: Birch seed is collected by picking the catkins while they are still green enough to hold together. They shatter easily and should be put directly into bags.
Seed Treatment: One month cold stratification compensates for light treatment.
Commercially Avail: yes
Find Seed or Plants
Find seed sources for this species at the Native Seed 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:
Santa Barbara Botanic Garden - Santa Barbara, CA
Native Seed Network - Corvallis, OR
Web ReferenceWebref 3 - Flora of North America (2014) Missouri Botanical Garden, St. Louis, MO & Harvard University Herbaria, Cambridge, MA.
Additional resourcesUSDA: Find Betula occidentalis in USDA Plants
FNA: Find Betula occidentalis in the Flora of North America (if available)
Google: Search Google for Betula occidentalis
MetadataRecord Modified: 2022-10-03
Research By: TWC Staff