Species: * Alnus = Alder (Unit 006) Alnus cordata = Italian Alder (Unit 006) * Alnus glutinosa = Black Alder, European Alder (Unit 006) Alnus incana = White Alder (Unit 006) Picture Notes: More Information: Distribution: About 30 species in N. Hemisphere and Andes mountains; deciduous, monoecious trees and shrubs. Synonyms: Hardiness Zone: USDA Zone (view USDA zone map) Size: Form: Bark: Stem/Bud: Leaves: Fall Color: Flower: Fruit: Uses: Wet sites. Problems: Culture: Links: Notes: Dirr and Barnes and Wagner say Alnus roots can fix atmospheric nitrogen in soil like Leguminosae. Notes 2: Deer resistant. Notes 3: Cultivars: