Blue Ash, present almost exclusively in the western half of Ohio, is the ash tree that is different in four respects from other Ashes found east of the Mississippi River.
First, it usually has square rather than round, young twigs that may be winged or corky. Second, its mature bark is usually scaly and platy rather than ridged and furrowed. Third, it does not have separate male and female trees, since all of its flowers are "perfect", and therefore every tree can yield fertile seeds under appropriate conditions. Fourth, the pioneers extracted a blue dye from its inner bark, giving it the common name of Blue Ash.
Like Green Ash and White Ash, the high-quality and slightly more dense wood of Blue Ash is harvested to make tool handles, furniture, and for use as firewood. However, its fall color is the poorest, being pale yellow to green in most years.
A native of midwestern North America, Blue Ash is often found at limestone outcrops and therefore thrives in dry soils of alkaline pH. It may grow to 80 feet tall by 40 feet wide, with a slow growth rate. Its shape is narrow upright when young, becoming upright rounded with maturity. As a member of the Olive Family, Blue Ash is related to other Ashes as well as the Fringe Trees, Forsythias, Privets, and Lilacs, plus the namesake of the family, the Olive Tree.
Planting Requirements - The preference of Blue Ash to alkaline soils (that is, those of high pH) accounts for its primary distribution in western Ohio, where the glaciated soils tend to be "sweet", rather than "sour". It often occurs at limestone outcrops, where the underlying rock gives the subsoil and topsoil a higher pH. Blue Ash adapts to a variety of stresses, especially to poor, dry, rocky soils. It grows in full sun to partial sun, and is found in zones 4 to 7.
Potential Problems - Like other ash trees, Blue Ash is occasionally susceptible to borers and scales as pests, and leaf anthracnose and trunk canker as diseases. In addition, seed litter from all trees and surface roots (with age in compacted or shallow soils) are potential liabilities in urban areas. Since it is slower-growing than most other ashes, storm damage does not occur as frequently, as its wood is more dense and stronger.
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.