Black ash have opposite, compound leaves with 7 to 13 leaflets. The leaflets are 3 to 5 inches long, with a toothed margin, without a stalk, dark green above and paler green below. Because it typically grows in wet, cold soils it is one of the last trees in the swampy woods to put out its leaves in the spring and the first to drop them in the fall. Black Ash trees can be mistaken for being dead when they are only waiting for enough warmth to put their leaves.

Black Ash is a culturally important species to the Ojibwe. Strips of wood were used in basket-making, and in traditional medical practices an infusion of inner bark was used for sore eyes.