Smooth Alder
Alnus serrulata
Last reviewed: June 2026
Alnus serrulata is a native deciduous shrub found throughout eastern North America from Maine to Florida and west to Texas. It blooms from March to May and thrives in wet soils along streams and wetlands.
The USDA PLANTS Database (opens in new tab) does not flag Smooth Alder as toxic to livestock.
Light
full sun
Water
high
Size
144"–240" H × 60"–120" W
Bloom
Mar, Apr, May
Native to
AL, AR, CT, DE and 25 more states
Browse plants for this ecoregion
Smooth Alder is a large native shrub that thrives in wet areas and grows 12-20 feet tall with a 5-10 foot spread. It produces catkins in spring and prefers consistently moist to wet soil conditions. This deciduous shrub works well for naturalizing wet spots or creating screening in areas with poor drainage.
Growing Smooth Alder
Grow Smooth Alder in full sun and high water. Mature plants reach 144 to 240 inches tall and spread 60 to 120 inches wide. Expect low maintenance to keep it looking intentional in a front yard.
In an HOA neighborhood
Smooth Alder takes more care to keep looking intentional in a front yard. Maintenance level: low. Consider it for backyard or mid-zone beds rather than the street edge.
Works well in: backyard only.
- Height exceeds typical HOA-friendly range
Wildlife value
The catkins provide early spring pollen for bees and other insects when few other plants are blooming. Birds use the dense branching for nesting and feed on the small nutlets produced later in the season.
Common questions
- Where does Smooth Alder naturally grow?
- Smooth Alder is native to the eastern United States, ranging from Maine south to Florida and west to Texas, Oklahoma, Missouri, and Illinois. It typically grows along streams, swamps, and other wetland areas.
- When does Alnus serrulata bloom?
- Smooth Alder blooms from March through May, producing catkins before the leaves emerge in early spring.
- What growing conditions does Smooth Alder prefer?
- This shrub prefers consistently moist to wet soils and can tolerate full sun to partial shade. It is commonly found in riparian zones and wetland margins where water availability is high.
- How big does Alnus serrulata get?
- Smooth Alder typically grows as a multi-stemmed shrub reaching 6-12 feet in height, though it can occasionally reach 15-20 feet under optimal conditions.
- Is Smooth Alder toxic to livestock?
- The USDA PLANTS Database does not flag Smooth Alder as toxic to livestock.
- Is Smooth Alder HOA-friendly?
- Smooth Alder takes more care to look intentional in a front yard. Consider it for backyard or mid-zone beds rather than the street edge.
Native range data from the USDA PLANTS Database and regional native plant society lists. Pollinator and host plant associations compiled from GBIF, iNaturalist, and published ecological literature.
Does Smooth Alder fit your yard? Open it in Pollinator Patch to check it against your sun, soil, and HOA-conscious filters.