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Blue ash identification: leaves, bark, fruit and twigs
Blue ash, Fraxinus quadrangulata, is a native tree in Pennsylvania. How to recognize it by its leaves, bark, fruit and twigs, and how to tell it from look-alikes.
Opposite, compound leaves. Compound leaves 7 to 11 inches long with 7 to 11 toothed leaflets, shiny on top. Bark: Ashy gray to brown, rough and scaly, later with scaly ridges. Checked Nov. 14, 2026.
How to identify blue ash
| Leaf type | Opposite, compound leaves |
|---|---|
| Leaves | Compound leaves 7 to 11 inches long with 7 to 11 toothed leaflets, shiny on top. |
| Bark | Ashy gray to brown, rough and scaly, later with scaly ridges. |
| Fruit | Wide-winged seeds 1 to 1 1/2 inches long. |
| Twigs | Stout twigs that are distinctly four-sided, sometimes winged: the easiest way to know this ash. |
| Size and shape | Up to about 70 feet with a short trunk. |
From the Virginia Tech Dendrology fact sheet, in our own words.
Is blue ash native to Pennsylvania?
The Pennsylvania Natural Heritage Program (PNHP) lists blue ash as native to Pennsylvania.
See all 140 trees, with a 4-question identifier, in our Pennsylvania tree identification guide.
Trees that look like blue ash
| Tree | Its leaves |
|---|---|
| Green ash Fraxinus pennsylvanica | Opposite, compound leaves. Compound leaves 6 to 9 inches long with 7 to 9 toothed, narrow leaflets, smooth or silky underneath. |
| White ash Fraxinus americana | Opposite, compound leaves. Compound leaves 8 to 12 inches long with 7 leaflets that are toothed or smooth-edged and paler underneath. |
| Black ash Fraxinus nigra | Opposite, compound leaves. Compound leaves 10 to 14 inches long with 7 to 11 toothed leaflets that have no stalks, with brown hair tufts underneath. |
Compare the leaves first, then the bark, fruit and twigs on each tree’s page.
Other ashes in Pennsylvania
Pumpkin ash (Fraxinus profunda).
Questions
How do you identify blue ash?
Look for opposite, compound leaves. Compound leaves 7 to 11 inches long with 7 to 11 toothed leaflets, shiny on top. Bark: Ashy gray to brown, rough and scaly, later with scaly ridges.
Is blue ash native to Pennsylvania?
The Pennsylvania Natural Heritage Program (PNHP) lists blue ash as native to Pennsylvania.
How big does blue ash get?
Up to about 70 feet with a short trunk.
How can you tell blue ash in winter?
Check the twigs and bark. Twigs: Stout twigs that are distinctly four-sided, sometimes winged: the easiest way to know this ash. Bark: Ashy gray to brown, rough and scaly, later with scaly ridges.
What tree looks like blue ash?
Green ash, White ash, Black ash. Compare the leaves first.
Sources: Virginia Tech Dendrology (Fraxinus quadrangulata fact sheet); Pennsylvania Natural Heritage Program, PA Vascular Plant List (native or introduced status). Checked Nov. 14, 2026.
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