Post Oak is a deciduous tree that may grow 40 to 50 feet tall and is common in the poorer soils of the Piedmont but is also found in the mountains to an elevation of 2,500 feet. It is native to central and eastern USA. It has a dense rounded to irregular form with the upper branches and stems often being twisted and gnarled. The tree has alternate leaves with 5 lobes and a hairy, pale underside. The two middle lobes are distinctly square, resulting in an overall cruciform appearance. Post Oak is tolerant of various soil types and prefers acidic well-drained soil in full sun. It is resistant to drought, fire and diseases. Use in the lawn as a shade tree, in naturalized areas or as a street tree. Oak trees will attract a variety of birds, moths, butterflies and mammals to your yard, providing them with food and shelter. It is a host plant for the larvae of the Imperial moth ( Eacles imperialis ) , as well as numerous butterflies, including Banded hairstreak ( Satyrium calanus ) , Edward's hairstreak ( Satyrium edwardsii ) , Gray hairstreak ( Strymon melinus ) , White-m hairstreak ( Parrhasius malbum ) , Horace's duskywing ( Erynnis horatius ) , and Juvenalis duskywing ( Erynnis juvenalis ) . Insects, Diseases, and Other Plant Problems: No pests or diseases of major concern but the tree occasionally succumbs to Chestnut blight and is susceptible to oak wilt. Quick ID Hints: leaves alternate, simple, 4-8" long, 3-4" wide 3 prominent lobes at apex 2-3 broad leaf pairs, middle pair largest
Curated pairwise relationships between this plant and others in the library — who feeds
whom, who competes, who confuses the pests. Green reads as a good pairing, red as one to avoid.
No curated interactions recorded for this species yet.
Also noted by NC State
Related species the NC State Plant Toolbox flags for this plant — look-alikes to tell
apart, and plants that play a similar role in a planting. Ones we carry in the library are linked.
Full sun (6 or more hours of direct sunlight a day)
Soil texture
Clay; Loam (Silt); Sand; Shallow Rocky
Soil pH
Acid (<6.0); Neutral (6.0-8.0)
Soil drainage
Good Drainage | Occasionally Dry
Available space
more than 60 feet
NC region
Coastal; Mountains; Piedmont
Mature size
Height: 40 ft. 0 in. - 50 ft. 0 in. | Width: 35 ft. 0 in. - 50 ft. 0 in.
Growth rate
Medium
Maintenance
Medium
Canopy layer
1 - Canopy (>40 ft)
Form & Appearance
Habit / form
Dense; Erect; Irregular; Rounded; Spreading
Texture
Medium
Foliage
Deciduous
Leaf color
Brown/Copper; Green
Leaf type
Simple
Leaf arrangement
Alternate
Leaf shape
Elliptical; Obovate
Leaf margin
Entire; Lobed
Leaf feel
Leathery
Leaf size
3-6 inches long, 3-6 inches wide
Hairs present
Yes
Leaf detail
Leathery green leaves are 3 to 8 inches long with wavy to deeply lobed margins with pinnate and reticulated venation. The lobes are rounded and up to 4 on each side with the upper pair often much larger than the others giving it a maltese cross shape. Fall color varies from non-showy brown to yellow and leaves may persist into winter.
Fall color
Brown/Copper; Gold/Yellow; Insignificant
Flower color
Brown/Copper; Gold/Yellow; Green
Flower form
Catkin; Insignificant
Flower detail
Male flowers occur in drooping yellowish catkins. Female flowers are shorter and occur near the tips of twigs. Also male green catkin. Blooms in April
Bloom time
Spring
Fruit color
Brown/Copper; Red/Burgundy
Fruit type
Nut
Fruit size
< 1 inch long
Fruit detail
The brown, egg-shaped acorns are produced either solitary or in pairs and are either sessile or short-stalked. They are 1/2 to 3/4 inch long with caps extending to about one-third of the length of the acorn. The caps have small appressed scales that are light gray or light tan. Acorns are reddish-brown and ½ inch to 1 inch long. Displays from September to November.
Bark color
Dark Brown; Dark Gray; Light Gray
Bark detail
The bark is scaly in younger trees. Mature trees with gray to brownish-gray, rough-textured, and ridged with horizontal cross-breaks
Stem color
Brown/Copper; Gray/Silver
Stem detail
Branch bark and larger twigs are gray and more smooth, while smaller twigs and young shoots are pale brown and densely short-pubescent.
Wildlife & Ecology
Native status
Native
Origin
Central and Eastern United States
Distribution
AL , AR , CT , DC , DE , FL , GA , IA , IL , IN , KS , KY , LA , MA , MD , MO , MS , NC , NJ , NY , OH , OK , PA , RI , SC , TN , TX , VA , WV. Eastern and central United States: Massachusetts and New York south to Florida, and west to Texas, Kansas, Missouri, and Iowa.
Wildlife value
Oak trees support a wide variety of Lepidopteran. You may see Imperial Moth (Eacles imperialis) larvae which have one brood per season and appear from April-October in the south. Adult Imperial Moths do not feed. Banded Hairstreak (Satyrium calanus), which have one flight from June-August everywhere but Florida where they emerge April-May. Edward's Hairstreak (Satyrium edwardsii), has one flight from May-July in the south and June-July in the north. Gray Hairstreak (Strymon melinus), has three to four flights in the south from February-November and two flights in the north from May-September. White-M Hairstreak (Parrhasius m-album) has three broods in the north from February-October. Horace’s Duskywing (Erynnis horatius) has three broods in Texas and the deep south from January-November, and two broods in the north from April-September. Juvenal’s Duskywing (Erynnis juvenalis) has one brood from April-June, appearing as early as January in Florida. The acorns are eaten by woodpeckers, blue jays, small mammals, wild turkeys, white-tailed deer, and black bear.
Attracts
Butterflies; Moths; Pollinators; Small Mammals; Songbirds
Play value
Wildlife Food Source
Food & Medicine
Harvest time
Fall
Fruit type
Nut
Edibility
Acorns are edible once the tannins have been leached or boiled out.
Uses (ethnobotany)
Wood is marketed as White Oak and used for construction timbers, posts and railroad cross-ties.