Alnus serrulata

Common Names

Smooth Alder, Hazel Alder, Common Alder, Tag Alder, Brookside Alder

Summary

Smooth Alder is a native deciduous shrub or small tree of eastern North America, often forming dense, multi-stemmed thickets with an open to ascending crown, reaching about 10 to 20 feet in height. It features smooth gray-brown bark, leathery obovate leaves with finely serrated margins, and wind-pollinated catkins that appear in spring, followed by cone-like fruits with winged seeds that persist into winter. Nitrogen-fixing roots and a tendency to sucker produce extensive root systems and dense stands, making it an effective riparian stabilizer along streams, ponds, and wetlands. It prefers full sun to part shade and moist to wet soils, is flood-tolerant, and tolerates a range of moisture conditions and soil types. It is commonly used for erosion control, restoration, and naturalization along stream banks, river margins, and pond borders, and supports wildlife; it can spread by suckers to form colonies and can be propagated by seed or cuttings. Hardiness zones 4a–9b reflect broad climate tolerance.

Lifecycle

Perennial

Height

10-20 feet

Spread

13-20 feet

Hardiness Zones

Zones 4-9

Sunlight Requirements

Ideally full Sun.

Soil Type

Moist to wet soils near streams or riverbanks, clay, loam, or sand soils

Soil Drainage

Moist to wet, poorly drained soils

Soil pH

Tolerates all pH levels

Bloom Color

Yellow-brown, Red

Bloom Time

Spring

Foliage Color

Dark green on the upper surface with paler green beneath; fall foliage turns yellow tinged with red

Fall Foliage Color

Yellow, tinged with red

Leaf Lifecycle

Deciduous

Growth Rate

Fast

Seasons of Interest

Spring, Fall, Winter

Propagation Methods

Seeds and Cuttings, Division

Attracts Wildlife

Attracts bees, butterflies, birds, and other pollinators