Ohio Trees - White Ash

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White Ash (Fraxinus americana)
A deciduous tree from the Olive Family (Oleaceae)

4-9
50'
70'
medium to rapid
full sun
part shade
upright oval
to upright rounded
Rich, moist, well-drained
acidic to neutral pH

White Ash, one of the more common and rapidly growing trees of forests and fields in all of Ohio, is also a popular shade tree for urban areas. From the forest, its wood is harvested to make baseball bats, toolhandles, furniture, and for use as firewood. Among the ashes, its wood is considered the best.

As a shade tree, it is known for its rapid growth and dependable fall color. One of the first trees to change color in autumn, its leaves often go through shades of yellow, orange, red, and purple. Its stems are thicker than those of Green Ash and Blue Ash, giving it a more bold texture in winter.

A native of eastern North America, White Ash is found mostly in cut-over forests, open fields, and fencerows. Under ideal conditions in the open, it grows to 70 feet tall by 50 feet wide, with a medium to rapid growth rate. Its shape is upright oval when young, becoming upright spreading to rounded with maturity. As a member of the Olive Family, White Ash is related to the Fringe Trees, Forsythias, Privets, and Lilacs, as well as other species of Ash.

Planting Requirements - Rich, moist, well-drained soils of acidic to neutral pH are ideal for growing White Ash. It is not quite as stress-tolerant as Green Ash or Blue Ash, especially to prolonged drought, occasional flooding, or very alkaline (high pH) soils. It grows in full sun to partial sun, and is found in zones 4 to 9.

Potential Problems - Among the common ash trees, White Ash is the most likely to encounter a problem during its lifetime, although most trees live a long and healthy life. Borers and scales are occasional pests, leaf anthracnose is a frequent cosmetic disease of the leaves when wet springs occur, and trunk canker is an occasional disease of the bark and cambium. In addition, seed litter (from female trees), surface roots (with age in compacted or shallow soils), and storm damage (at maturity due to splittable wood and narrow crotch angles) are potential liabilities, primarily in urban areas.

Emerald Ash Borer(Agrilus planipennis), is a destructive exotic pest from Asia. This metallic wood-boring beetle attacks all of Ohio's native ash species, and has no known significant natural enemies in this country. EAB has been discovered infesting ash trees in Michigan, Ohio, Indiana, and Illinois. The first Ohio discovery was in Lucas County in February of 2003

Leaf Identification Features
Leaves of White Ash are opposite, pinnately compound, and have 5 to 9 dark green leaflets (usually seven or nine) with white-green undersides (shown as a detached leaflet, being the reason that White Ash is so-named).

The leaflets are smooth or only sparsely serrated on their margins, with short stalks that attach to the central rachis. The vibrant autumn color of White Ash often starts as yellow and orange, then may transition to red and purple for some trees.

Other Identification Features

Male flowers and female flowers occur on separate trees of White Ash in late winter or early spring, and thus the male and female trees are termed "dioecious".

Both types of flowers occur before the leaves emerge and often go unnoticed, since they are relatively small and do not have petals.

Fruits (known as samaras) hang in clusters from female trees of White Ash, with each fruit being composed of a plump anchoring seed attached to a wing (for a thinner version, see Green Ash).

The mature fruits of the ashes separate and spin downward like helicopter blades in autumn.

When the leaves of White Ash drop in autumn, they leave behind U-shaped leaf scars on the twigs, like a wide horseshoe.

A small lateral bud rests within the curved portion of the "U".

The stout, ascending twigs of White Ash are thicker than those of Green Ash and Blue Ash, and give this tree a bolder texture in winter.

The smooth young bark of White Ash does not become flaky like that of Green Ash, but eventually forms interlacing ridges and furrows, yielding mature bark which is identical in appearance to that of Green Ash.

Ohio Department of Natural Resources