Trees of Iowa: An Interactive Key

Green Ash
(Fraxinus pennsylvanica)

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Green ash is one of our most adaptable native trees. Green ash is characterized by having opposite, pinnately compound leaves with 5 to 9 leaflets (usually 7). The leaves are 10 to 12 inches in length with individual leaflets 2 to 6 inches long. The leaflets are long-pointed at the tip with a tapering base. The leaflet stalks are 1/16 to 3/16 inches in length, often with a slight winged appearance. The leaflets are dark green and glossy on the upper surface, while lighter green below. The margins are usually conspicuously toothed.

Green Ash LeavesGreen Ash Fruit
Hardiness: zones 3 through 9

Growth Rate:
Moderate to Fast

Mature Shape:
Slightly pyramidal, upright with a rounded crown

50-80 feet

50-70 feet

Site Requirements:
Native to Iowa, ash trees grow best in full sun and moist, well-drained soils. Ash trees are tolerant of a wide range of soil conditions.

Flowering Dates: March - May

Seed Dispersal Dates: October - Spring

Seed Bearing Age: 10 years

Seed Bearing Frequency: Yearly

Seed Stratification: Warm stratification for 2 months at 68°F followed by prechilling for 2-5 months at 34°F to 40°F.

Branches are stout, round, green and smooth to hairy when young, becoming smooth and turning ash-gray with age with half circular leaf scars. The fruit is a paddle-shaped samara which often persists into winter. The bark is ashy-gray or gray-brown, furrowed, with narrow interconnecting ridges enclosing diamond-shaped spaces. 

Green Ash TwigGreen Ash Flowers

Green ash is the most widely distributed ash in the United States. It is native to all of Iowa. It is found most often growing on bottomlands or on wet upland sites. Its common associates include cottonwood, silver maple, willows, hackberry, and black walnut. It does however, grow remarkable well on a wide variety of sites and if often found as a common tree of wood edges on upland sites. 

Green Ash Form

Like white ash, its wood is hard, tough, and relatively straight grained and used for a variety of products from tool handles to furniture to pallets. 

Green ash is the fastest growing of the ashes, attaining heights of 50 to 70 feet. It has been used extensively for a shade tree because of its adaptability and relatively fast growth rate. Most shade tree selections are male to avoid seed production. It turns a golden yellow in the fall.


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Green Ash Twig Green Ash Twig Green Ash Twig Green Ash Flower Green Ash Leaves Green Ash Fruit Green Ash Form Green Ash Fruit