White Oak

Scientific Name: Quercus alba. Quercus is a Latin name used specifically for oak trees. There are over 350 species of oaks! The light gray bark is the reason the species name is alba, meaning white.^1,4,6

Common Name: White Oak. The common name comes from the light color of the wood of this tree. Other common names are occasionally used, but most still contain “white” as part of the name: American white oak, eastern white oak, northern white oak, and forked-leaf white oak for example. Did you know that the oak tree (any species from the genus Quercus) was chosen to be the national tree of the United States?^3,4

Family: Fagaceae (Beech Family). The roughly 800+ species in this family primarily grow in the Northern Hemisphere but also may be found in southeast Asia and Australia. They are trees or shrubs that are monoecious (having both male and female flowers on the same plant). The leaves are undivided (although they may be lobed), alternate, and pinnately veined (having veins on either side of a central vein). The fruits are nuts with 1 seed and are fully or partly enclosed by a cupule (think cap or spiny bur!) that can be helpful in identification. Can you think of any other trees that would be in this family? The American chestnut and American beech are examples, but the most numerous in our area are oak trees! Trees in this family are often dominant in our forests, providing habitat and food for numerous insects and other animals!^5,6

Average Height: 60-100 ft. but up to 135 ft.

Description: This large, deciduous tree is named for its light gray bark that varies from flat, flaky plates to a more blocky pattern. Twigs are red-brown to gray and hairless (or become so with age). The medium to dark green leaves alternate on the twigs and measure 4-9” long and 2-4 ½” wide. Each leaf has 3-5 pairs of shallow to deeply-cut lobes with rounded tips and is hairless and pale underneath. Trees are monoecious, with both male and female flowers growing on the same tree. Yellowish-green male flowers are densely clustered on a dangling catkin about 2-3 ½” long while the small, greenish-red female flowers grow on short stems and are less noticeable. Flowers are wind-pollinated and mature into oval acorns roughly ¾” long with caps covered in warty scales. About ⅛ – ½ of the nut is covered by the cap which separates when the nut is mature.^1,2,4,6,7

Bloom time: Apr

Notes: Oaks in our area can be classified broadly as white oaks or red oaks. Examples of white oaks include species such as white oak (Quercus alba), chestnut oak (Quercus montana), and post oak (Quercus stellata), while red oaks include northern red oak (Quercus rubra), southern red oak (Quercus falcata), black oak (Quercus velutina), and scarlet oak (Quercus coccinea). One key characteristic can help you narrow down what type you are looking at – the leaves and lobes of white oaks do not have bristles (short, stiff hairs), while those of the red oaks are bristle-tipped! Several other interesting characteristics distinguish white oaks from red oaks. Acorns of white oaks mature in 1 year and root in the fall while those of red oaks take 2 years to mature and root in the spring. In addition, the inner surface of the acorn caps are hairless in white oaks and hairy in red oaks.⁶ Take a close look at the leaves and acorns the next time you see an oak!

Range: Common and widespread across the state, the white oak grows in all counties of Virginia and is likely our most common oak.⁸ Grows from Maine to Florida and as far west as Minnesota south to eastern Texas. Found also in Ontario and Quebec.^9,10

Geology/Soil: Grows well in rich, dry to moist, well-drained soils that are slightly acidic, but also found on a wide range of other soil types and is tolerant of drought.^1,3,4,8

Habitat: Most commonly found in moist to dry upland forests and woodlands, but may also sometimes be found in well-drained ravines, flatwoods, depression swamps, and bottomlands.^2,6,8

Flora associations: Due to its prevalence in a wide variety of plant communities, it can be found with many different trees and plants. In the canopy these include other oaks (Quercus spp.), hickory species (Carya spp.), pine species (Pinus spp.), American beech (Fagus grandifolia) and tulip-tree (Liriodendron tulipifera). Plants in the understory can vary from those that grow well in nutrient-rich soils to those that grow in infertile soils – the white oak can be a dominant species in either type of site! What other trees and plants do you see growing here?

Fauna associations: Oaks (Quercus spp.) serve an incredible role in forests as host plants for over 1,000 species of butterfly and moth caterpillars! In addition, all parts of the tree provide food and habitat for a wide variety of animals and all those caterpillars are a vital food source for many birds.¹⁴

Butterfly species such as sleepy duskywing (Erynnis brizo), Juvenal’s duskywing (Erynnis juvenalis), the northern oak hairstreak (Satyrium favonius ontario), white-m hairstreak (Parrhasius m-album), and the banded hairstreak (Satyrium calanus) use the white oak as a host plant. Included among the hundreds of moth species that feed on Quercus alba are caterpillars of the shagreened slug moth (Apoda biguttata), girlfriend underwing moth (Catocala amica), red-fringed emerald moth (Nemoria bistriaria), solitary oak leafminer moth (Cameraria hamadryadella), and lobelia dagger moth (Acronicta lobeliae).^2,16

In addition to caterpillars, oaks support a wide-range of other insects including a dazzling array of leafhoppers, treehoppers, beetles, midges, parasitic gall wasps, aphids, and more! The grubs of the parasitic wool sower gall wasp (Callirhytis seminator) develop within puffy white galls with reddish dots that are formed on white oak stems or leaves.^2,13,16 (See photo!)

The acorns are eaten by chipmunks, squirrels, wild turkeys, white-tailed deer, black bears, and many more animals! Jays such as the eastern blue jay (Cyanocitta cristata) are closely linked to oak trees. Not only do they eat acorns, but they also cache large numbers of them in the ground, some of which grow into oak seedlings. Some studies show that individual birds may cache over 100 acorns per day! Jays are believed to be instrumental in the spread of oaks after the last ice age!^2,15

Human associations: Over time, humans have found a variety of medicinal and other uses for Quercus alba. This hardwood is used widely for fuel, furniture, flooring, barrels, boats, railroad ties, basket making, and more. Many Indigenous Peoples including the Cherokee, Ojibwa, and Haudenosaunee developed methods for removing the tannins from the acorns to make them edible. They also use infusions from the bark to treat sore skin, coughs, sore throats, diarrhea, muscular pain, and asthma. The bark is used for mouth sores, as an emetic, and as an antiseptic. Awls, mortars, furniture, and baskets are made from the wood of the white oak.^2,11,12

We want these plants to thrive and for everyone who gets to visit the park to enjoy them, so remember – don’t pick flowers or other parts of the plant!!

1 “Quercus Alba – Plant Finder.” Missouribotanicalgarden.org, 2019, www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?kempercode=l930. Accessed 24 Jan. 2025.

2 “White Oak (Quercus Alba).” Illinoiswildflowers.info, 2019, www.illinoiswildflowers.info/trees/plants/white_oak.html. Accessed 24 Jan. 2025.

3 “Vascular Plants of North Carolina.” Ncparks.gov, 2019, auth1.dpr.ncparks.gov/flora/plant_list.php. Accessed 24 Jan. 2025.

4 “Quercus Alba (Oaks, White Oak) | North Carolina Extension Gardener Plant Toolbox.” Plants.ces.ncsu.edu, plants.ces.ncsu.edu/plants/quercus-alba/. Accessed 24 Jan. 2025.

5 “Fagaceae – FNA.” Floranorthamerica.org, 5 Nov. 2020, floranorthamerica.org/Fagaceae.

6 Weakley, A.S., J.C. Ludwig, and J.F. Townsend. 2012. Flora of Virginia. Bland Crowder, ed. Foundation of the Flora of Virginia Project, Inc., Richmond. Fort Worth: Botanical Research Institute of Texas Press, pp. 607-619.

7 “Virginia Tech Dendrology Fact Sheet.” Vt.edu, 2021, dendro.cnre.vt.edu/dendrology/syllabus/factsheet.cfm?ID=35. Accessed 24 Jan. 2025.

8 “Digital Atlas of the Virginia Flora | Quercus Alba Linnaeus.” Vaplantatlas.org, 2025, www.vaplantatlas.org/index.php?do=plant&plant=3322&search=Search. Accessed 24 Jan. 2025.

9 “2014 BONAP Maps by States – Quercus alba.” Bonap.net, 2025, bonap.net/FieldMaps/Home/SingleMap?taxonId=12042&mapType=County. Accessed 24 Jan. 2025.

10 “NatureServe Explorer 2.0.” Explorer.natureserve.org, explorer.natureserve.org/Taxon/ELEMENT_GLOBAL.2.138617/Quercus_alba. Accessed 24 Jan. 2025.

11 “BRIT – Native American Ethnobotany Database.” Brit.org, 2025, naeb.brit.org/uses/search/?string=quercus+alba. Accessed 24 Jan. 2025.

12 “White Oak (Quercus Alba).” My Cherokee Garden, 22 Feb. 2016, mycherokeegarden.com/2016/02/22/white-oak-quercus-alba/. Accessed 24 Jan. 2025.

13 Baker, James. “Wool Sower Gall Wasp | NC State Extension Publications.” Ncsu.edu, 1 Mar. 2022, content.ces.ncsu.edu/wool-sower-gall-wasp. Accessed 27 Jan. 2025.

14 Cubie, Doreen. “Want to Nurture Wildlife? Plant a Native Oak.” National Wildlife Federation, 26 Sept. 2024, www.nwf.org/Magazines/National-Wildlife/2024/Fall/Gardening/Planting-Oak-Trees. Accessed 27 Jan. 2025.

15 Thomas Scott. “Jays Plant Acorns – UC Oaks.” UC Oaks, 29 Dec. 2018, oaks.cnr.berkeley.edu/jays-plant-acorns/. Accessed 27 Jan. 2025.

16 “Search – Quercus Alba.” Bugguide.net, 2024, bugguide.net/index.php?q=search&keys=quercus+alba&search=Search. Accessed 27 Jan. 2025.

Definitions:

Monecious: Having both male and female flowers on the same plant.