Blue Ash
 

Mature Size, Growth, Longevity

Habit is a narrow, upright, irregular, rounded crown, with a slender, straight, slightly-tapered trunk, reaching 50-70' tall in most landscapes, although the national champion is 120' by 132' in Mason, KY. Moderate growth rate. Medium genetic longevity potential, often living for 100-150 years.

Native Range

Kentucky Native — Native to the east-central to southeastern states, and from Michigan to Arkansas and Tennessee, including parts of Kentucky, Ohio and Indiana. Introduced in 1823.

Flower and Fruit Details

Monoecious flowers, green to purple, in April/May, appearing with the new leaves. Tan/brown, single samara fruits are 1" long, in dense, drooping clusters, July-February.

Leaf and Bark Features

Deciduous: Twigs bearing the leaves are somewhat "square" due to the 4-angled, corky wings. Leaves are opposite, pinnately compound, 7-14" long, with 5-7 (to 11) leaflets, each 2-5" long and 1-2"wide, dark green and glabrous above, with pubescent midribs beneath. Leaves turn a pale yellow to golden yellow in the fall. Drops leaves early, like most ash trees. Distinctive, gray to gray-brown bark that is thin, broken into irregular, scaly plates, or shaggy, not grooved. The tree's name relates to the inner bark, which contains a blue mucilaginous substance that turns blue when exposed to the air.

Culture and Care

Often found on dry, alkaline soils. Tolerates pH 6.6-8.0. This is an upland tree, not a river bottom plant. Quite heat and drought tolerant. Zone 4-7. Avoid low, wet areas. Does not tolerate flooding. Pollution-tolerant. Intermediate salt tolerance. Susceptible to ash anthracnose and various ash borers, but seems to be less susceptible to the emerald ash borer than green ash or white ash.

Strengths, Weaknesses, Other Facts

3-season interest: Spring, Summer and Fall.

Suggested Uses

Used as a shade tree or park tree, or on tough sites such as in dry, alkaline soils.

Taxa and Plants of this Species at BCA