After featuring a number of lesser-known natives over the past several newsletters, we turn this month to a staple Mid-Atlantic native tree, the willow oak (Quercus phellos), which we last featured in 2017. Surprisingly for a tree that gets its common name from the resemblance of its foliage to willow (Salix) leaves, Q. phellos is a member of the red oak section of the oak family (subg Quercus, sect Lobatæ). The willow oak is a native of the SE coastal plain, from Long Island to north Florida and westward to east Texas and inland to the Appalachians. It rarely appears at elevations above 400 m (1300 ft). Compared to other native oak, it is typically somewhat less massive, with a mature height usually at 20-30 m (65-100 ft) with a trunk 1 to 1½ m (3 ½-5 ft) in diameter.
In youth, Q. phellos is a relatively fast-growing tree, up to 60 cm / 2 ft a year. Its oblong to pyramidal habit when young gradually widens to a broad, rounded form with maturity. The bright-green willow-like leaves typically turn gold or russet in autumn and as is typical for red oaks, are tipped with a soft bristle. The narrow leaves contribute to an overall fine-textured appearance, which is relatively unusual—and desirable—in a larger shade tree. The lightly-furrowed bark is a medium grey. Willow oak is typically a prolific acorn producer. Fruiting begins at a young age, 15-20 years old; the acorns are relatively small, about 1½ cm / ½ inch in diameter and nearly round.
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Willow oak typically prefers bottomlands and moist situations in its native range. In the landscape, willow oak is easy to transplant, but requires regular watering in dry periods for the first few years. Best results for B&B transplants are achieved by digging the tree during dormancy (e g, after the killing frosts of autumn). With maturity, Q. phellos becomes relatively drought-tolerant and is highly adaptable to urban sites. Caution, however, is prudent in selecting planting sites as the tree has a relatively shallow root structure and can cause heaving of sidewalks and other pavements. It is a high-value wildlife tree with its acorn yield as well as a larval host to the imperial moth (Eacles imperialis) and a half-dozen species of butterflies, including hairstreaks.
Commercially, willow oak is valuable as timber due to its fast growth in youth; as a red oak group member, its lumber is typically sold as generic ‘red oak’ in the trade.
For autumn 2024, WHN has good supply of willow oaks from 1½” to 3½” caliper. Get your order in today!
