- Blue Ash redirects here. For other uses, see Blue Ash (disambiguation)
Fraxinus quadrangulata (Blue Ash) is a species of Fraxinus native primarily to the Midwestern United States, as well as the Bluegrass region of Kentucky and the Nashville Basin region of Tennessee. Isolated populations exist in Alabama, Southern Ontario, and small sections of the Appalachian Mountains. It is typically found over calcareous substrates such as limestone, growing on limestone slopes and in moist valley soils, at elevations of 120–600 m.
It is a medium-sized deciduous tree typically reaching a height of 10–25 m with a trunk 50–100 cm diameter. The twigs typically have four corky ridges, a distinctive feature giving them a square appearance (in cross-section), hence the species name, quadrangulata, meaning four-angled. The winter buds are reddish-brown. The leaves are 20–38 cm long, with 5–11 (most often 7) leaflets, the leaflets 7–13 cm long and 2.5–5 cm broad, with a coarsely serrated margin and short but distinct petiolules. The flowers are small and purplish, produced in the early spring before the leaves appear. The fruit is a samara 2.5–5 cm long and 6–12 mm broad, including the wing.
The name Blue Ash is derived from the blue dye extracted from the tree's inner bark through immersion in water. European colonists and American pioneers used this dye to color yarn for use in the production of textiles, sewing, crocheting, knitting, weaving, and embroidery. Blue Ash wood is used to make flooring, baseball bats, furniture, tool handles, crates and barrels. The city of Blue Ash, Ohio, an inner suburb of Cincinnati, drew its name from the blue ash trees in the area, the logs of which were used to build many of the community's earliest buildings.