shrubN. America Native

Smooth Alder

Alnus serrulata

Not currently listed at our partner nurseries.

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Essentials

At a Glance

Plant Type

Shrub

Height

180 inches

Width

144 inches

Light

Full Sun, Partial Sun

Zones

4, 5, 6, 7, 8, 9

Water

High

Humidity

High

Lifespan

Medium-lived shrub/tree

Native To

Eastern North America

Toxicity

Non-toxic

The Story

Plant Bio

Alnus serrulata is a multi-stemmed deciduous shrub or small tree native to eastern North America, typically found along streams, ponds, and in wet areas. It is known for its nitrogen-fixing abilities and distinctive woody, cone-like fruits that persist through winter. This species is particularly valuable for wetland restoration and stabilizing stream banks due to its tolerance for saturated soils and its soil-improving qualities. The dangling male catkins are attractive in late winter.

Bloom Period:

EarlyLate

Uses & Benefits:

Offers a naturalistic aesthetic with interesting winter structure from its persistent cones and dangling catkins. It's a key component of a native plant or woodland garden.

Its primary practical use is in soil stabilization and erosion control along waterways. As a nitrogen-fixing plant, it improves the soil for surrounding vegetation.

It is a host plant for the larvae of several butterfly and moth species. The seeds in the 'cones' are eaten by birds like finches and siskins, and the thickets provide cover for wildlife.

Marketplace

Where to Buy

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Planting

How to Grow

Choose a site with consistently moist to wet soil.
Dig a hole as deep and twice as wide as the root ball.
Set the plant in the hole with the crown at soil level.
Backfill with native soil, as it's adapted to poor soils.
Water deeply after planting to eliminate air pockets.
Mulching is beneficial but not essential in its native wet habitat.

Pro Tip

Ideal for problem wet spots in the landscape where other shrubs fail to thrive.

Keep It Thriving

Care Guide

Do

Provide ample moisture; this plant does not tolerate drought.
Plant in acidic soil for best performance.
Allow it to form a natural thicket for erosion control.

Don't

Don't plant in dry, alkaline soils.
Don't expect showy flowers or fall color.
Don't remove the nitrogen-fixing root nodules.

Seasonal Care Calendar

Task	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Plant
Prune

Watch Out For

Pests & Diseases

Common Pests

Common Diseases

In the Garden

Landscape Uses & Companions

Landscape Uses

Excellent for rain gardens and boggy areasNaturalizing along ponds and streamsEffective for erosion control on wet slopes

Companion Plants

Salix nigra Cephalanthus occidentalis Cornus sericea Juncus effusus Iris versicolor

Multiply

Propagation Methods

Good to Know

Common Questions

Smooth Alder questions

What zones can Smooth Alder grow in?

Smooth Alder is hardy in USDA Zones 4–9. Inside that range it survives winter in the ground; outside it, grow it as an annual or a container plant you protect.

Is Smooth Alder deer resistant?

Yes — Smooth Alder is rated deer-resistant. Deer typically pass it over, though extreme hunger can override any plant's defenses.

When does Smooth Alder bloom?

Smooth Alder typically blooms in late winter through early spring. Exact timing shifts a week or two with your zone — Sow's bloom calendar maps it to your garden.

Does Smooth Alder need full sun?

Smooth Alder does best in full sun to part shade. In hot climates, afternoon shade keeps blooms fresher longer.

Keep exploring

Explore the genus

All Alnus varieties

Collections featuring this plant

Hardy in your zone?

Grow Smooth Alder with confidence

See it in a design of your actual yard, get zone-matched care reminders, and track it season by season in your garden journal.