Alnus glutinosa (L.) Gaertn.
Synonym: black alder, European alder, European black alder
Paul Wray, Iowa State University
Forestry and Natural Areas
Black alder is a mid-sized tree that can grow up 50 feet tall. It has simple; alternate leaves often with biserrate (double toothed) leaves. Black alder grows best in low lying areas with moist, acidic soils. It is commonly found along stream banks and other waterways. This plant's tendency to be dispersed by water, and its ability to form mono-specific stands, makes it a threat to native wetland species. Black alder can fix nitrogen, giving it the ability to become established on very poor soils. <www.invasive.org>
In 100 Years of Change in the Distribution of Common Indiana Weeds by William and Edith Overlease (2002) reported that black alder was not found in Indiana in 1899 (Coulter’s Catalogue of Indiana Plants); however, it was reported in 1940 (Deam’s Flora) in St. Joseph county but not herbarium specimen was submitted. In 2002 (Overlease) reported black alder Clay, Jackson, and Marion counties in Indiana.