treeN. America Native

September Elm

Ulmus serotina

The Story

Plant Bio

Ulmus serotina is a medium-sized deciduous tree native to the south-central and southeastern United States, reaching up to sixty-five feet tall with a broad, rounded canopy. Its alternate obovate leaves feature double-serrate margins and distinct oblique bases that turn yellow in fall.

Unlike most native North American elms that bloom in spring, this species produces apetalous green flowers in pendulous racemes during fall. Older branches develop prominent corky wings along the bark that persist through winter.

Uses & Benefits:

Provides shade with a rounded canopy and winter visual interest from corky branch ridges.

Tolerates dry, shallow soils derived from limestone outcrops where other shade trees fail.

Seeds feed native songbirds and small mammals while twigs offer browse for wild game.

Essentials

At a Glance

Plant Type

Tree

Height

787"

Width

708"

Light

Full Sun, Partial Sun

Zones

5, 6, 7, 8, 9

Water

Moderate

Humidity

Moderate

Lifespan

Perennial

Native To

North America

Toxicity

Non-toxic

Bloom period

Fall

In flower about 3 months of the year

Planting

How to Grow

Plant in a full sun to light shade location with well-drained clay, loam, or limestone-derived soil.
Water deeply weekly during the first two growing seasons until the root system is fully established.
Apply a three-inch layer of organic mulch around the root zone, keeping it clear of the trunk base.
Prune dead, damaged, or crossing branches during winter dormancy to maintain structure and airflow.

Pro Tip

Differentiate September elm from cedar elm by observing its autumn flower clusters alongside developing seed samaras rather than early spring blooms.

Keep It Thriving

Care Guide

Do

Plant in well-drained soil where water does not pool after heavy rains.
Prune during winter dormancy to minimize exposure to vector insects.
Monitor foliage and trunk bark regularly for signs of fungal wilting or borer damage.

Don't

Do not prune live wood during spring and summer when bark beetles are actively foraging.
Do not allow mulch to pile up directly against the trunk bark.
Do not fertilize heavily unless soil tests show severe nutrient deficiencies.

Seasonal Care Calendar

Task	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Mulch
Pest Check
Prune
Spring Cleanup

Watch Out For

Pests & Diseases

Common Pests

Common Diseases

In the Garden

Landscape Uses & Companions

Landscape Uses

Shade TreeNaturalizingPark Tree

Companion Plants

Celtis occidentalis Quercus alba Cercis canadensis Acer saccharum

Multiply

Propagation Methods

Good to Know

Common Questions

September Elm questions

What zones can September Elm grow in?

September Elm is hardy in USDA Zones 5–9. Inside that range it survives winter in the ground; outside it, grow it as an annual or a container plant you protect.

Is September Elm deer resistant?

Not reliably. Deer may browse September Elm, especially tender spring growth — plan on repellents or fencing where pressure is high.

When does September Elm bloom?

September Elm typically blooms in fall through fall. Exact timing shifts a week or two with your zone — Sow's bloom calendar maps it to your garden.

Does September Elm need full sun?

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

Is September Elm drought tolerant?

Yes — once established (usually after the first full season), September Elm handles dry spells with minimal watering. Water deeply its first year to build the root system that makes that possible.