How to Manage and Identify Green Ash

Green ash trees will reach a height of about 60 feet with a spread of 45 feet. Upright main branches bear twigs which droop toward the ground before bending upward at their tips much like basswood. The glossy dark green foliage will turn yellow in the fall, but the color is often muted in southern regions.

There is a good seed-set annually on female trees which are used by many birds but some consider the seeds to be messy. This fast-growing tree will adapt to many different landscape conditions and can be grown on wet or dry sites, preferring moist. Some cities have over-planted green ash.

Specifics of the Green Ash

• Scientific name: Fraxinus pennsylvanica
• Pronunciation: FRACK-sih-nus pen-sill-VAN-ih-kuh
• Common name(s): Green Ash
• Family: Oleaceae
• USDA hardiness zones: 3 through 9A
• Origin: Native to North America
• Uses: Large parking lot islands, wide tree lawns, recommended for buffer strips around parking lots or for median strip plantings in the highway, reclamation planting, shade tree
• Availability: Generally available in many areas within its hardiness range

Native Range

Green ash extends from Cape Breton Island in Nova Scotia, Canada, west to southeastern Alberta; south through central Montana, northeastern Wyoming, to southeastern Texas; and east to northwestern Florida and Georgia.

Description

Leaf: The leaves are described as "opposite, pinnately compound," meaning they're divided into smaller leaflets on either side of a central stalk. Each section contains 7 to 9 serrate (tooth-edged) leaflets that are lanceolate (shaped like a lance or narrow oval with pointy ends) to elliptical in shape. The entire leaf is 6 to 9 inches long, green above, and anywhere from smooth to slightly downy below. (Official botanical terms are glabrous to silky-pubescent.)

Crown uniformity: Symmetrical canopy with a regular (or smooth) outline, and individuals have more or less identical crown forms.

Trunk/bark/branches: Grow mostly upright and will not droop; not particularly showy; should be grown with a single leader; no thorns.

Breakage: Susceptible to breakage either at the crotch due to poor collar formation, or the wood itself is weak and tends to break.

Flower and Fruit

Flower: Dioecious (male and female reproductive organs are located in separate individuals); light green to purplish, both sexes lacking petals, females occurring in loose clusters, males in tighter clusters. Flowers appear after the leaves unfold.

Fruit: A single-winged, dry, flattened samara (winged seed capsule) with a slender, thin seed cavity, maturing in autumn and dispersing over winter.

Special Uses

Green ash wood, because of its strength, hardness, high shock resistance, and excellent bending qualities, is used in specialty items such as tool handles and baseball bats, but is not as desirable as white ash. It is also a favorite tree used in city and yard landscapes.

Several Green Ash Hybrids

"Marshall Seedless" has some seeds, yellow fall color, fewer insect problems. "Patmore" is an excellent street tree, straight trunk, good yellow fall color, seedless. "Summit" is female, yellow fall color, straight trunk but pruning required to develop strong structure, abundant seeds, and flower galls can be a nuisance. "Cimmaron" is a new plant (USDA hardiness zone 3) reported to have a strong trunk, good lateral branching habit, and tolerance to salt.

Damaging Pests

Borers: Common on ash and they can kill trees. The most common ones are ash borer, lilac borer, and carpenter worm. Ash borer bores into the trunk at or near the soil line causing tree dieback. The emerald ash borer has already killed countless trees in North America. According to Natural Resources Canada, "No North American natural predators, such as woodpeckers, other insects or parasites have been able to slow the spread of the emerald ash borer or keep trees from being killed by it."

Anthracnose: Also called leaf scorch and leaf spot. Infected parts of the leaves turn brown, especially along the margins. Infected leaves fall prematurely. Rake up and destroy infected leaves. Chemical controls are not practical or economical on large hardwood trees. Trees in the South can be severely affected, and major tree loss can affect property values.

The Most Widely Distributed 

Green ash (Fraxinus pennsylvanica), also called red ash, swamp ash, and water ash is the most widely distributed of all the American ashes. Naturally a moist bottomland or stream bank tree, it is hardy to climatic extremes and has been widely planted in the Plains states and Canada. The commercial supply is mostly in the South.

Green ash is similar in property to white ash and they are marketed together as white ash. The large seed crops provide food to many kinds of wildlife. Due to its good form and resistance to insects and disease, it is a very popular ornamental tree. Hardy, fast-growing green ash is a popular choice for reforestation on spoil banks after strip mining.