Natural History

White Ash

Fraxinus americana – Olive family (Oleaceae)

Leaves:
Leaves are pinnately compound. Each leaf has 7 or more leaflets. Leaflets are ovate to elliptical. All leaflets on one leaf are usually about the same size. Leaflets are dark green above, whitish below. Leaflets are larger than Black Walnut leaflets.  

Bark:
Bark is ashy gray in color. Bark is furrowed. Corky ridges form diamond-shaped grooves in the bark.

Flowers:
Flowers are very small, produced in small clusters. Flowers emerge before leaves in the spring. Male and female flowers are on separate trees (dioecious).

Fruit:
Fruit is 1to 2 inches long, dry, brown. Fruit looks like the blade of a canoe paddle in outline with the seed at the handle end. Seed is almost entirely surrounded by the wing. Fruit hangs in clusters, matures in late summer, wind-dispersed.

Emerald Ash Borer:

Emerald ash borer (EAB), Agrilus planipennis, is an Asian beetle, discovered in 2002 in southeastern Michigan and Windsor, Ontario. The EAB infests and kills ash trees. Damage is caused by the larvae, which feed in tunnels just below the bark. The tunnels cut off water and nutrient transport, causing branches and eventually the entire tree to die. Adult beetles leave distinctive D-shaped exit holes in the outer bark of branches and the trunk.

Adults EABs are roughly 1/2 inch long with metallic green wing covers and a coppery red or purple abdomen. They may be present from late May through early September but are most common in June and July.

The EAB has not been observed in Putnam County, at least, not yet, but has been observed in Marion County and is more abundant in northeastern Indiana.

More information about the Emerald Ash Borer

• Where EAB has been found in Indiana
• Symptoms of EAB on ash trees
• Poster describing EAB life cycle

White Ash leaf.
(photo source #13)

White Ash bark. (photo source #5)

White Ash fruit (photo source #7)

Adult emerald ash borer
(photo source #19)