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Willow oak identification: leaves, bark, fruit and twigs
Willow oak, Quercus phellos, 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.
Alternate, simple leaves with smooth edges. Narrow, willow-like leaves 2 to 5 inches long with smooth edges and a bristle at the tip. Bark: Smooth, gray and tight when young; later rough ridges and furrows. Checked Nov. 14, 2026.
How to identify willow oak
| Leaf type | Alternate, simple leaves with smooth edges |
|---|---|
| Leaves | Narrow, willow-like leaves 2 to 5 inches long with smooth edges and a bristle at the tip. |
| Bark | Smooth, gray and tight when young; later rough ridges and furrows. |
| Fruit | Very small round acorns 1/4 to 1/2 inch with a thin saucer cap. |
| Twigs | Slender, hairless olive-brown twigs. |
| Size and shape | Up to about 80 feet with a dense oblong crown in the open. |
From the Virginia Tech Dendrology fact sheet, in our own words.
Is willow oak native to Pennsylvania?
The Pennsylvania Natural Heritage Program (PNHP) lists willow oak as native to Pennsylvania, with some wild populations that also grew from planted trees.
See all 140 trees, with a 4-question identifier, in our Pennsylvania tree identification guide.
Trees that look like willow oak
| Tree | Its leaves |
|---|---|
| Shingle oak Quercus imbricaria | Alternate, simple leaves with smooth edges. Unlobed, shiny, leathery leaves 3 to 7 inches long with a single bristle at the tip, fuzzy underneath. |
Compare the leaves first, then the bark, fruit and twigs on each tree’s page.
Other oaks in Pennsylvania
White oak (Quercus alba), Swamp white oak (Quercus bicolor), Scarlet oak (Quercus coccinea), Southern red oak (Quercus falcata), Bear oak (Quercus ilicifolia), Blackjack oak (Quercus marilandica), Swamp chestnut oak (Quercus michauxii), Chestnut oak (Quercus montana), Chinkapin oak (Quercus muehlenbergii), Pin oak (Quercus palustris), Northern red oak (Quercus rubra), Shumard oak (Quercus shumardii), Post oak (Quercus stellata), Black oak (Quercus velutina), English oak (Quercus robur), Sawtooth oak (Quercus acutissima).
Questions
How do you identify willow oak?
Look for alternate, simple leaves with smooth edges. Narrow, willow-like leaves 2 to 5 inches long with smooth edges and a bristle at the tip. Bark: Smooth, gray and tight when young; later rough ridges and furrows.
Is willow oak native to Pennsylvania?
The Pennsylvania Natural Heritage Program (PNHP) lists willow oak as native to Pennsylvania, with some wild populations that also grew from planted trees.
How big does willow oak get?
Up to about 80 feet with a dense oblong crown in the open.
How can you tell willow oak in winter?
Check the twigs and bark. Twigs: Slender, hairless olive-brown twigs. Bark: Smooth, gray and tight when young; later rough ridges and furrows.
What tree looks like willow oak?
Shingle oak. Compare the leaves first.
Sources: Virginia Tech Dendrology (Quercus phellos fact sheet); Pennsylvania Natural Heritage Program, PA Vascular Plant List (native or introduced status). Checked Nov. 14, 2026.
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