Fraxinus quadrangulata Michx.

See herbarium specimen records | See photo gallery

Common names:
blue ash, blue ash
Growth form:
Small to medium-sized tree,
10 - 20 m tall, trunk diameter 30 cm - 0.5 m.
narrow and rounded with many short, sturdy branches.
light gray tinged with red, moderately thin, and irregularly divided into large, scaly plates that give the trunk a slightly shaggy appearance.
stout and square, with short, corky ridges extending between the nodes, orangish with rusty hairs, becoming brownish gray and hairless. Leaf scars crescent-shaped, with several bundle scars forming a U.
dark reddish brown, small, rounded, and slightly hairy. Terminal bud 6 - 8 mm long and blunt. Uppermost pair of lateral buds adjacent to the terminal bud at nearly the same level.
opposite, pinnately compound, 20 - 38 cm long, with five to eleven leaflets (usually seven). Leaflets short-stalked, yellowish green above, paler with tufts of hairs along the veins beneath, 7 - 13 cm long, 2.5 - 5 cm wide, oblong egg-shaped to lance-shaped with a tapering base and long-pointed tip, coarsely toothed, thick, and firm. Leaves turn yellow in autumn.
borne in a branched inflorescence, purplish, small, and lacking petals.
dry, single-seeded, winged (samara), 2.5 - 5 cm long, oblong and notched at the tip. Wing broad, often twisted, extending to the base of the flat seed cavity and surrounding it.
Plant Glossary
Similar species:
The square stems of Fraxinus quadrangulata immediately distinguishes it from any other ash in the Chicago Region.
April to mid-May, as leaves begin to unfold
Habitat and ecology:
Typically found in calcareous woodlands and wet-mesic sites.
Regional occurrence:
The inner bark of Fraxinus quadrangulata was once soaked in water to produce a blue dye, and its sap will turn blue when exposed to the air. The wood is used for flooring and interior finish, and the tree is sometimes planted as an ornamental. The emerald ash borer (Agrilus planipennis) is a serious insect threat to all native ashes (see link below).
Fraxinus is the Latin word for ash. Quadrangulata is Latin for "four-angled," which refers to the square twigs.
name code: FRQU ; page author: The Morton Arboretum ; page date: 2006-12-03
Further information (external links):
Google: Text Search Image Search
[ We can not vouch for content of other websites ]
Barnes, B. V., and W. H. Wagner, Jr. 2004. Michigan trees: A guide to the trees of the Great Lakes region. Ann Arbor, MI: University of Michigan Press.
Little, E. L. 1980. National Audubon Society field guide to North American trees: Eastern region. New York: Alfred A. Knopf: Distributed by Random House.
Mohlenbrock, R. H. 1996. Forest trees of Illinois. 8th ed. Illinois: Illinois Department of Natural Resources, Division of Forest Resources.

Specimens by county

Fraxinus quadrangulata

Click any county or state for specimens from that area.

Or click here for specimen records from all counties.

Information provided on this page applies to the Chicago Region and may not be relevant or complete for other regions.