Betula pendula is an introduced European tree species that is now found in North America. In the US, it is reported from CO, CT, IA, IL, IN, KY, MA, ME, MI, NH, NJ, NY, OH, OR, PA, VA, VT, WA, WI, and, in Canada, it is reported from BC, MB, NB, NS, ON, PE (USDA 2010). In British Columbia, it is found in the southwestern corner of the province, and is well established in the Fraser River delta where it has heavily invaded bogs and is widespread. Like other birches, it hybridizes readily, and can produce hybrid swarms. It is tolerant of acid wet conditions and will grow in brackish water (Klinkenberg, personal observation). The earliest specimen record for this species in the UBC Herbarium is a collection from the Fraser River delta by Vladimir Krajina in 1948, from the Lulu Island Bog.
References: USDA. 2010. Plant profile for Betula pendula. United States Department of Agriculture. Available Online.
Deciduous tree, 10-30 m tall; bark thick, rough, dark brown, furrowed, often peeling; twigs glandular, numerous small glands, sometimes sticky; branch ends often drooping.
Alternate, deciduous, wedge-shaped in outline, saw-toothed, glabrous below, 1-6 cm long.
Male and female flowers in separate catkins, the male 3-6 cm long, the female 1.5-3.5 cm long; flowers emerging before or with the leaves; catkins breaking up at maturity.
Nutlets with broad wings, at least twice as wide as the body of the nutlets; bracts with rounded lateral lobes.
If more than one illustration is available for a species (e.g., separate illustrations were provided for two subspecies) then links to the separate images will be provided below. Note that individual subspecies or varietal illustrations are not always available.
Illustration Source: The Illustrated Flora of British Columbia
Present over the Summer
Source: The USDA
Synonyms and Alternate Names:
Betula verrucosa Ehrh.
The genus Betula is known for its prolific hybridization that has resulted in difficult to identify hybrid swarms (Brayshaw 1996).
Brayshaw, T. Christopher. 1996. Catkin-bearing Plants of British Columbia. Royal British Columbia Museum, Victoria.