Alnus incana (L.) Moench

Grey alder, tag alder, speckled alder, gray alder

These fast-growing trees are often found beside wet areas. Alder roots, like many legumes, are capable of converting atmospheric nitrogen into usable nutrients, allowing them to grow in relatively infertile soil. These densely branched shrubs, with their penchant for growing in muddy soil and rapid spread by creating clonal colonies, form nearly impassable thickets.

Plants: Small to medium in size, often with multiple trunks and branches. Speckled alders grow to 12–36′ (3.7–10 m), rarely reaching 60′ (18 m), usually less than 20′ (6.1 m) tall. “Speckled” refers to the presence of many lenticels—white, or light gray or orange oval patches, wider than they are flat, on the trunk.

Leaves: Dark green, alternate, roughly oval, 2–4″ (5–10 cm) long, and doubly serrated.

Flowers: Male flowers are catkins 1½–3½″ (3.8–8.9 cm) long. Female flowers are cylindrical catkins attached directly to the branch, ⅛″ (4.8 mm) long.

Fruits: Egg-shaped cones about ⅝ ⨉ ¼″ (1.6 cm ⨉ 7.9 mm), green at first, becoming dark brown and often persisting through the winter.

Habitats: Swamps and wetlands.

Online References:

Alnus incana description by Thomas H. Kent, not updated.

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