Hazel Alder
Alnus serrulata
Betulaceae - Birch Family
Hazel alder, also known as common alder, smooth alder, green alder, American alder, and swamp alder, has a bushy growth from that grows 5 to 20 feet high. It has serrated, thick oval leaves from 2 to 4 1/2 inches long. Male flowers are borne in pedulous catkins, while female flowers grow in upright catkins. The fruits are hard and cone-like, and remain on the plant over winter.1
This tree is native to eastern North America, ranging from Maine to Florida and west to the plains states.2 It grows well in wet, swampy areas and along the banks of rivers, ponds, and lakes; however, it can also grow in upland habitats.2 It has a thick fibrous root system, and so it is ideal for stabilizing banks and protecting against bank erosion. Alders harbor nitrogen-fixing bacteria in root nodules. For this reason, it is not recommended for planting in areas where additional nitrogen might add to water quality problems. For bank stabilization, plants should be planted 2 feet apart. For seed production for wildlife, plantings should be 10 feet apart to stimulate crown development and seed production.
References and Useful Websites:
1Herbhunters - Purdue University
2 Garden Guides
This page was prepared by Rachel Gilbert, BIO 102, Fall 2011