Black Alder, also called European Alder or European Black Alder (Alnus glutinosa Gaerten, Family Betulaceae)

Description of Plant

Leaf: Found in 3 rows, 1 1/4 - 4" long, 1- 2 1/2' wide; eliptical to nearly round; doubly saw-toothed with 5 to 7 parallel veins on each side.
Flower: Male catkins are 1 - 1 1/2" long, female flowers which are found in the cones are 1/4" long.
Cones: 5/8 - 7/8" long, in clusters of 3 to 5; eliptical or egg-shaped, black, hard gummy and long-stalked.
Twig: Mostly hairless, with 3-angled pith.
Bark: Brown; smooth becoming furrowed into broad plates.
Form: Straight trunk with rounded or oblong crown of dark green foliage.
Discussion: This introduced native ornamental tree is found in wet soils and humid, cool conditions. Can reach a height of 50-70' with a 1-2' trunk diameter.
Distribution: Introduced to U.S. and found throughout. Native of Europe, Asia and N. Africa. Naturalized locally in SE Canada and the NE U.S.




 Typical Growth Form of Young Tree

 Characteristic Leaf


 Black Alder Reproductive Structures (Measured in Inches)


Mature Catkins(left) and Mature Cones (right)


Backyard, 803 E. Olympian Road, Urbana, IL, USA.


Spring, 2003 Organismal Biology Class and David M. Stone (Instructor), University Laboratory High School, Urbana, IL. Please contact for permission for use of these images. Permission will generally be granted for education- and non-profit-related use.

More, David and John White, The Illustrated Encyclopedia of Trees, Timber Press, Portland, Oregon, 2002.
Petrides, George, A Field Guide to Eastern Trees, Peterson Field Guide Series, Houghton Mifflin Company, 1988.
National Audubon Society Field Guide to North American Trees: Eastern Region, Alfred A. Knopf. New York, 1996.
Trees of North America, Golden Press, New York, 1986.

Developed 5/03. Last modified 6/24/03.