Dr. Mark D. Robinson, MD
Willow Oak (Quercus phellos)
This tree is dedicated in honor of Dr. Mark D. Robinson, MD by the residents of Cabarrus Family Medicine Residency on the occasion of his retirement October 2018.
Description: These are wonderful urban trees that grow to form majestic tall canopies that line streets and avenues such as along Union Street in Concord. Willow oak is a medium to large deciduous tree, a member of the red oak group, it is identified by its thin willow-like leaves that are quite unlike typical oak leaves. Compared to other oaks it has a faster growth rate and typically grows 40-75 feet tall and 30-40 feet wide with an oval or rounded crown. In ideal settings it can grow to 100 feet tall. Its bark is smooth, gray and tight on younger trees, but develops rough ridges as the tree ages.
Leaves: The leaves are alternate, simple, smooth-edged, bristle tipped, narrow and greening and average 5” long and 1” wide. The leaves are not particularly showy in fall as they turn a dull yellow brown. This tree is commonly called “pin oak” by the public, but that is a separate species.
Flowers: Unremarkable yellowish-green flowers in separate male and female catkins appear on the Willow Oak in spring (April) as the leaves emerge.
Fruit: Small ½ inch acorns often produced in alternate years of heavy bearing.
Habitat: This tree thrives in the Piedmont of NC as it is tolerant of heat and drought. It also is a good choice for cities as it tolerates air pollution and standing water. The willow oak adapts to a wide range of soil conditions including clays. It grows best in average, medium to wet, well-drained soils in full sun.
Wildlife value: It is a host plant for several butterflies and many moths. Its acorns are eaten by woodpeckers, songbirds, ducks, small mammals, wild turkeys, white-tailed deer, quail and black bears. The acorns are toxic to humans and cause gastrointestinal symptoms if ingested.
Uses: This tree is a good one to plant along margins of fluctuating level water reservoirs for erosion control. The wood is used for lumber, crossties, construction and used to make cabinetry, furniture, interior trim, flooring, and veneer.
History: Quercus phellos was reportedly a favorite tree of Thomas Jefferson. There are many planted around Washington, D.C. In North Carolina there are champion big tree willow oaks in Sampson and Union county. (https://www.ncforestservice.gov/Urban/big_species_results.asp)
Sources: Native plants of the Southeast: a comprehensive guide to the best 460 species for the garden. Larry Mellichamp; photographs by Will Stuart-1st ed. 2014 Timber Press, Portland, Oregon, ISBN 978-1-60469-323-2. NCSU Plant database. https://plants.ces.ncsu.edu/plants/quercus-phellos/ USDA Plant fact sheet. https://plants.usda.gov/factsheet/pdf/fs_quph.pdf