A Willow Oak (Quercus phellos) blends the solid structure of the red oak family — think of the Northern Red Oak or the lesser known but similarly impressive Shumard Oak1 — with the fine-textured appearance of a willow tree’s leaves. Given room to grow in full sun, it is magnificent.
In its early years, the Willow Oak has a pyramidal shape, with a straight, slender trunk and leaves massed on thin branches. Over time this youthful form expands outward and upward as the crown rounds into a globe. The simple, lance-like leaves create an airy feel above a trunk that becomes stout with age.
Native from New Jersey to Texas2, the Willow Oak has a hardiness range of Zones 5 to 9, although the northern part of that range may be pushing its tolerance for cold3,4. Preferring moist soil and sun when growing in the wild, the Willow Oak adapts to a variety of challenging conditions such as drought and clay soil, making it an option for less than ideal environments.
Willow Oaks are large trees, filling out to 75′ or more in height and 50′ across. With the lower branches removed, or limbed up, they work well along roadways and in picnic areas and parks, stretching overhead and providing shade.
And what incredible shade, a broad, cool reach patterned with sunlight.
The leaves that create this dappled expanse emerge, as with many oaks, later in the season than the foliage of most other deciduous trees. Thin, bronze, and bamboo-like from a distance, the leaves slowly lengthen and widen, mimicking the willow’s leaf shape as they deepen from light to dark green. Fall brings shades of yellow before leaf drop and bare limbs unusual for most oaks in winter5.
Oaks provide habitat and nourishment for the caterpillars many bird species rely on for food6, and for the Willow Oak this includes larvae of the Banded Hairstreak, Gray Hairstreak, and Juvenal’s Duskywing7. The plentiful supply of acorns produced every other year feeds foxes, jays, woodpeckers, and deer.
Once you’re familiar with Willow Oaks, you’ll start seeing these elegant, native shade trees everywhere, especially in the Southeast and Mid-Atlantic. It’s not difficult to understand why.
1. Jensen, Richard J. “5a. Quercus Sect. Lobatae G. Don in J. C. Loudon, Hort. Brit. 385. 1830.” Flora of North America, Vol 3. Fagaceae. Accessed July 20, 2019. http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=302020
2. “Quercus phellos.” Native Plants of North America Plant Database. The University of Texas at Austin Lady Bird Johnson Wildflower Center. Accessed July 14, 2019. https://www.wildflower.org/plants/result.php?id_plant=QUPH
3. “Quercus phellos.” Plant Finder, Missouri Botanical Garden. Accessed July 14, 2019. http://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?taxonid=280755&isprofile=1&basic=quercus%20phellos
4. Dove, Tony and Ginger Woolridge. Essential Native Trees and Shrubs for the Eastern United States. 2018. Watertown, Massachusetts: Charlesbridge. p. 153-155.
5. Finley, Jim. “Winter Leaves that Hang On.” News. PennState College of Agricultural Sciences, Department of Ecosystem Science and Management, Center for Private Forests. Posted: December 17, 2012. Accessed July 14, 2019. https://ecosystems.psu.edu/research/centers/private-forests/news/2012/winter-leaves-that-hang-on
6. Tallamy, Douglas W. Bringing Nature Home: How You Can Sustain Wildlife with Native Plants. Updated and expanded paperback edition, 2009. Portland, Oregon: Timber Press. p. 148-153.
7. “Quercus phellos.” North Carolina Extension Gardener Plant Toolbox. N.C. Cooperative Extension. Accessed July 20, 2019. https://plants.ces.ncsu.edu/plants/quercus-phellos/
If you’d like to read more:
Dirr, Michael A. and Keith S. Warren. “Quercus phellos – willow oak.” The Tree Book. 2019. Portland, Oregon: Timber Press. p. 756-759.
“Host Plants for Butterfly and Moth Caterpillars: Eastern Temperate Forests Ecoregion.” Native Plant Finder. National Wildlife Federation, U.S. Forest Service, University of Delaware. Accessed July 20, 2019. https://www.nwf.org/-/media/Documents/PDFs/Garden-for-Wildlife/Eco-Regions/Eastern-Temperate-Forests_Plant-List.ashx?la=en&hash=616D5224A08F6939620441CFECE9BA90B9496712
Ober, Holly K. “The Value of Oaks to Wildlife.” Department of Wildlife Ecology and Conservation, UF/IFAS Extension. Original publication date August 2008. Revised April 2014. Reviewed June 2017. Publication #WEC248. Accessed July 20, 2019. https://edis.ifas.ufl.edu/uw292
“Plants Profile for Quercus phellos (willow oak).” USDA, NRCS. 2019. The PLANTS Database (http://plants.usda.gov, 20 July 2019). National Plant Data Team, Greensboro, NC 27401-4901 USA. https://plants.usda.gov/core/profile?symbol=QUPH
“Quercus phellos – willow oak.” Virginia Tech Dendrology Factsheets. Virginia Tech College of Natural Resources and Environment. 2019. Accessed July 20, 2019. http://dendro.cnre.vt.edu/DENDROLOGY/syllabus/factsheet.cfm?ID=75
Note: This post was originally written on July 20, 2019 and revised on November 11, 2019.
Edgings Plant Bio #4