The Black Alder, Alnus glutinosa, is a rapid growing European native that thrives in truly wet soil. The grayish brown bark is complemented by nutlets that mature in October and persist in pistillate catkins over winter. Black Alder is a good choice where a large windbreak is needed, clumps have 2 or more stems. The Black Alder is a hardy tree, surviving northern winters well, though it does better in wet sites and can be short lived if grown in dry, stressful sites. The Alder is one of the few tree varieties that convert nitrogen from the soil atmosphere enabling it to grow and prosper even in adverse conditions. The Black Alder needs plenty of moisture to get established and will grow in heavily compacted soil if a moderate amount of water is available. The four-inch long leaves are dark green on the top and very light on the bottom. Greenish-yellow catkins with numerous tiny flowers are displayed in early spring before leaves appear. (Click Merchant link below for full description)