Ulmus americana var. floridana: Florida Elm

Introduction

This native North American tree grows quickly when young, forming a broad or upright, vase-shaped silhouette, 60 to 80 feet high and wide. The six-inch-long, deciduous leaves are dark green throughout the year, fading to yellow before dropping in fall. In early spring, before the new leaves unfold, the rather inconspicuous, small, green flowers appear on pendulous stalks. These blooms are followed by green, wafer-like seedpods which mature soon after flowering is finished and the seeds are quite popular with both birds and wildlife. American elm must be at least 15-years-old before it will bear seed. The copious amount of seeds can create a mess on hard surfaces for a period of time. Trees have an extensive but shallow root system.

General Information

Scientific name: Ulmus americana var. floridana

Pronunciation: UL-mus uh-mair-ih-KAY-nuh variety flor-ih-DAY-nuh

Common name(s): Florida elm

Family: Ulmaceae

USDA hardiness zones: 8A through 9B (Fig. 2)

Origin: native to North America

Invasive potential: little invasive potential

Uses: sidewalk cutout (tree pit); parking lot island > 200 sq ft; reclamation; street without sidewalk; tree lawn > 6 ft wide; shade; urban tolerant; highway median

Availability: somewhat available, may have to go out of the region to find the tree

Description

Height: 60 to 80 feet

Spread: 50 to 60 feet

Crown uniformity: symmetrical

Crown shape: vase, upright/erect

Crown density: moderate

Growth rate: fast

Texture: medium

Foliage

Leaf arrangement: alternate (Fig. 3)

Leaf type: simple

Leaf margin: double serrate

Leaf shape: oblong, ovate

Leaf venation: pinnate

Leaf type and persistence: deciduous

Leaf blade length: 2 to 4 inches, 4 to 8 inches

Leaf color: green

Fall color: yellow

Fall characteristic: not showy

Flower

Flower color: green

Flower characteristics: not showy

Fruit

Fruit shape: round

Fruit length: less than .5 inch, .5 to 1 inch

Fruit covering: dry or hard

Fruit color: green

Fruit characteristics: attracts birds; not showy; fruit/leaves a litter problem

Trunk and Branches

Trunk/bark/branches: branches don't droop; not showy; typically one trunk; thorns

Pruning requirement: needed for strong structure

Breakage: susceptible to breakage

Current year twig color: brown

Current year twig thickness: thin

Wood specific gravity: unknown

Culture

Light requirement: full sun, partial sun, or partial shade

Soil tolerances: clay; sand; loam; alkaline; acidic; extended flooding; well-drained

Drought tolerance: moderate

Aerosol salt tolerance: moderate

Other

Roots: not a problem

Winter interest: no

Outstanding tree: no

Ozone sensitivity: unknown

Verticillium wilt susceptibility: susceptible

Pest resistance: resistant to pests/diseases

Use and Management

Once a very popular and long-lived shade and street tree, American elm suffered, and is currently suffering, a dramatic decline in most areas in the north with the introduction of Dutch elm disease, a fungus spread by a bark beetle. The wood of American elm is very hard and was a valuable timber tree used for lumber, furniture and veneer. The Indians once made canoes out of American elm trunks, and early settlers would steam the wood so it could be bent to make barrels and wheel hoops. It was also used for the rockers on rocking chairs. Today, the wood that can be found is used mainly for making furniture.

American elm should be grown in full sun on well-drained, rich soil. If you plant American elm, plan on implementing a monitoring program to watch for symptoms of Dutch elm disease. It is vital to the health of existing trees that a program be in place to administer special care to these disease-sensitive trees.

Propagation is by seed or cuttings. Young plants transplant easily.

Pests

Many pests may infest elm, including bark beetles, elm borer, gypsy moth, mites, and scales.

Diseases

Many diseases may infect elm, including Dutch elm disease, phloem necrosis, leaf spot diseases, and cankers.