European Alder

(Alnus glutinosa)

Date Planted: October 2000

Family: Betulaceae

Hardiness: Hardy in the Gorham, ME area; Zone 4-7

Mature Dimensions: 40-60 feet tall, 20-40 feet wide

Habit: Pyramidal in youth; narrow-pyramidal in maturity

Bark: Young bark is shiny gray-green, turning to shiny brown with age

Buds: On stalks, reddish-brown, elliptical and ¼-1/2 inches in length

Leaves: Simple, alternate, 2-4 inches long, 3-4 inches wide; ½ to 1 inch petiole.
Rounded, dark green and shiny, coarsely and doubly serrate, with 6-8 vein pairs

Flowers: Monoecious, reddish brown male flowers borne in 2-4 inch catkins in clusters of 3-5; purplish female flowers borne in an egg-shaped strobile; appear in May

Fruit: Small winged nutlets are borne in 1/3-2/3 inch strobili; fruit matures in November and drops when strobile opens. Strobili persist into the winter season

Pests/Diseases: Tent caterpillar, cankers, sawfly, wooly alder aphid

Reference Pages: Dirr M. 1998. Manual of Woody Landscape Plants. Stipes Publishing Co., Champaign, IL.