Alnus glutinosa – Common Alder (central Europe)
Habit: Large tree, 8-20 (30) m tall, 8-10 m wide; conical to ovoid crown, branches horizontal to vertical, medium to fast-growing, 20-40 cm a year.
Flowers: Reddish-brown catkins, March.
Leaves: Roundish or reverse ovoid, dark green, somewhat shiny, leaves falling in October-November.
Roots: Intense flat to cordate roots, no runners, tolerates floods and covering, collect nitrogen.
Demands: Full sun to light shade; for cold to moderately warm areas, very frost hardy.
Soil: Fresh to damp, sensitive to drought when young; all acidic substrates except poor sandy soil, moderately tolerant of salt.
Hardiness: Zone 3