Fraxinus quadrangulata

Species Native to Missouri
Common Name: blue ash 
Type: Tree
Family: Oleaceae
Native Range: North America
Zone: 4 to 7
Height: 50.00 to 75.00 feet
Spread: 35.00 to 60.00 feet
Bloom Time: April to May
Bloom Description: Purple
Sun: Full sun
Water: Dry to medium
Maintenance: Medium
Suggested Use: Shade Tree, Street Tree
Flower: Insignificant
Attracts: Birds
Tolerate: Deer, Drought


Easily grown in average, dry to medium wet, well-drained soils in full sun. Prefers consistently moist, humusy loams, but is generally considered to be one of the best of the ashes for dry sites.

Noteworthy Characteristics

Fraxinus quadrangulata, commonly called blue ash, is native from Michigan south to Arkansas and Tennessee. In Missouri, it typically occurs in dry rocky woodlands, limestone glades and limestone bluffs in the Ozark region of the State (Steyermark). Early Americans made a blue dye from the inner bark, hence the common name. Corky-winged young twigs are distinctively four-sided, thus giving rise to another common name of winged ash. This is an upland species that typically grows 50-75’ tall with a narrow, irregularly rounded crown. Clusters of apetalous bisexual purplish flowers appear in April-May with the foliage. Flowers give way to drooping clusters of winged samaras (to 2” long) that ripen in fall and may persist on the tree throughout winter. Features odd-pinnate compound leaves, each with 7-11 lance-shaped, dark green leaflets (4-5” long). Leaves turn pale and usually dull yellow in fall. Grayish bark on mature trees separates into irregular plates. As with white ash, the wood of blue ash is commercially used for a variety of products including tool handles and furniture.

Genus name is the classical Latin name for ash trees.

Specific epithet means four-angled in reference to the unique four-sided twigs.


Emerald ash borer is native to Asia. It was first discovered in the U. S. (southeastern Michigan) in 2002. It has now spread to a number of additional states in the northeast and upper Midwest, and is expected to continue spreading. Emerald ash borer will typically kill an ash tree within 3-5 years after infestation. Once infestation occurs, it is very difficult to eradicate this pest which feeds under the bark and bores into wood. This borer now constitutes a serious threat to all species of ash in North America. Blue ash trees are generally susceptible to a number of additional insect problems including ash borer, lilac borer, carpenter worm, oyster shell scale, leaf miners, fall webworms, ash sawflies and ash leaf curl aphid. Potential disease problems include fungal leaf spots, powdery mildew, rust, anthracnose, cankers and ash yellows. General ash decline is also a concern. Brittle branches are susceptible to damage from high winds and snow/ice.


Planting new green ash trees is no longer recommended given the susceptibility of this tree to the emerald ash borer. Ash trees have typically been used over time in a variety of applications including shade tree, street tree or lawn tree.