Alnus serrulata (Smooth Alder)

A genuine nitrogen-fixing wetland specialist with a rapid growth rate, smooth alder stabilizes streambanks and pond margins while enriching the surrounding soil - a dependable, fast-establishing shrub for the wettest, most shaded corners of a restoration site.

Species Overview

Alnus serrulata, commonly called smooth alder or hazel alder, is a multi-stemmed deciduous shrub native to wetland habitats across eastern North America, typically growing 8 to 15 feet tall with a dense, rounded, thicket-forming habit. Small, reddish-brown catkins appear in early spring before leaf-out, and the plant tolerates full sun to full shade in consistently wet soils.

Application

• Streambank and pond-edge stabilization - extensive root system
• Wetland restoration - nitrogen-fixing soil improvement
• Rapid-establishment thicket and wildlife cover plantings
• Shaded wetland margins where few other shrubs tolerate full shade

Growing Conditions / Specification Data

• Light: Full Sun to Full Shade
• Soil/Moisture Tolerance: Wet, consistently moist soils; streambanks, pond margins, swamps
• Growth Rate: Rapid
• Drought Tolerance: Low
• Flood Tolerance: High - Very flood tolerant; needs constantly moist soil and is found naturally on stream banks, bogs, swamp borders, and wet meadows.
• Shade Tolerance: Tolerant
• Plant Type: Shrub
• Mature Height: 8-15 ft.
• Fall Color: Yellow to Red
• Bloom Color / Period: Brown; March-April
• Wetland Indicator Status: FACW (Facultative Wetland)
• Native Range: Nova Scotia south to Florida, west to Texas and Missouri - concentrated along the Atlantic and Gulf coastal plains.
• Hydrology: Wet
• Deer Resistance: Some
• Salinity Tolerance: None - freshwater wetland species
• Growth Habit: Multi-stemmed/Thicket-forming
• USDA Hardiness Zones: 5-9
• Root Depth: Moderate (12-24 in.)
• Pollinator Value: None significant

Planting Guidance

• Nitrogen-fixing capability enriches surrounding soil and promotes growth of nearby vegetation. Spreads rapidly by suckering to form dense thickets; historically used by Native American communities for medicinal purposes and as a natural dye.