Oak Trees of Pennsylvania
Red oaks have leaves with sharply pointed tips on 7 to 11 lobes. Susan Marquesen, Penn State Master Gardener
There are 90 native oak species in the United States, with fewer than 20 native to Pennsylvania. Oaks are a keystone species, meaning that they provide essential food and habitat for wildlife, particularly caterpillars, birds, and mammals. For success, site the right tree in the right place. Give your new tree the conditions that it prefers so that it will thrive. Make sure to plant and care for it properly until it gets established. When you plant one of the following species, or a cultivar, you are investing in the future. Any one of these oak trees will provide habitat for many species and beauty for many generations to come.
White Oak Family of Trees
The leaves of white oaks have rounded lobes, and their acorns mature in the first year. White oaks are generally thought to be less susceptible to oak wilt disease. Avoid pruning between April and November to reduce the risk of this deadly disease.
White oak (Quercus alba) is a popular and long-lived (up to 500 years) shade tree. It grows to 100 feet, with a wide-spreading, rounded crown and numerous horizontal branches. As with many other oaks, it is pyramidal in youth and becomes oval and spreading in maturity. The white oak prefers full sun to partial shade and coarse, deep, moist, well-drained, loamy, slightly acidic soil. It is adaptable to other soil types and is fairly drought-tolerant once established. Wet sites and compacted sites should be avoided. The deep taproot of a white oak makes it difficult to transplant. The tree is best propagated by seeds (acorns). USDA Plant Hardiness Zones 3 to 9.
Swamp white oak (Q. bicolor) is a large tree that grows to 100 feet with an irregular crown. Swamp white oak prefers full sun and moist to wet acidic soil with a high mineral content, but it is adaptable to drier sites. Due to its root system, it is tolerant of areas that have spring flooding and fairly dry summers. It is tolerant of heat and drought, but sensitive to soil compaction, salt, and air pollution. This tree is difficult to transplant and establish. USDA Plant Hardiness Zones 4 to 8.
Bur oak (Q. macrocarpa) is a slow-growing, large tree that grows to 100 feet, with a massive trunk, broad crown, and large and strong branches. The tree is drought-tolerant, cold-winter hardy, and isn’t seriously bothered by insects or diseases. It prefers rich bottomland but is tolerant of poor soil conditions such as rocky slopes and dry or clay soils. It does need full sun. A long taproot makes it difficult to transplant. USDA Plant Hardiness Zones 3 to 8.
Chestnut oak (Q. montana) is a medium to large tree, growing to a height of 65 to 145 feet, with a broad, open, and irregular crown and chestnut-like foliage. It is often found growing in poor, dry, and rocky soils but does best in well-drained loamy soil. Chestnut oak is tolerant of drought once established. USDA Plant Hardiness Zones 4 to 8.
Chinkapin oak (Q. muehlenbergii) is a medium to large tree, reaching 45 to 110 feet, with a narrow, rounded crown. Unlike most white oaks, it is tolerant of alkaline soil with a pH greater than 7. Chinkapin oak is an attractive tree that does best in moist-to-dry, well-drained soil but adapts to different soil types. USDA Plant Hardiness Zones 3 to 7.
Dwarf chinkapin oak (Q. prinoides) is a rhizomatous shrub or a small tree that tops out at 25 feet. It is found in sunny sites, often in rocky or acidic sandy soils on dry plains, rocky bluffs, ridges, and woodland edges. It is easily adaptable to garden loams for the home landscape and tolerates poor, dry soils. It has a deep taproot and is difficult to transplant. USDA Plant Hardiness Zones 5 to 8.
Post oak (Q. stellata) is a shrub to medium-sized tree with a dense, rounded crown. It is slow-growing, up to 85 feet, under exceptionally good environmental conditions. Post oak is tolerant of various soil types but prefers acidic, well-drained soil in full sun. It is resistant to drought, fire, and diseases. USDA Plant Hardiness Zones 5 to 9.
Red Oak Family of Trees
The leaves of red oaks generally have pointed or bristled lobes, and their acorns mature in two years. Avoid pruning between April and November to reduce the risk of oak wilt disease.
Scarlet oak (Q. coccinea) is a fast-growing large tree that can obtain a height of 120 feet, with numerous downward arching branches. The trunk is usually enlarged near the base. This oak usually retains its dead branches. It is valued for its vibrant scarlet red fall foliage and is often planted for its ornamental value. This tree is long-lived, durable, and easy to grow. It prefers acidic, sandy soils on the dry side, but it will tolerate other soil conditions as long as the soil drains well. The scarlet oak, like many oaks, is difficult to transplant due to its tap root. It does not develop chlorosis as often as other oaks. USDA Plant Hardiness Zones 4 to 9.
Scrub (or bear) oak (Q. ilicifolia) is a deciduous shrub or small tree, which normally grows to a height of 18 feet and occasionally to 41 feet. It prefers sandy, rocky, or shallow soils. It favors strongly to moderately acidic soils but is adaptable. However, it does not do well in wet, waterlogged, or clayey sites. Exceptional drainage is the key. Scrub oak would be an excellent choice for poor-quality, degraded land where other plants struggle. USDA Plant Hardiness Zones 5 to 8.
Shingle (or laurel) oak (Q. imbricaria) is a medium-sized tree that normally grows to 65 feet, occasionally to 105 feet. It has a rounded crown. The leaves of the shingle oak have no lobes, making it project a “finer” texture than many oaks. It tolerates a wide range of soil types, drought, and full sun. It is not salt-tolerant. Shingle oak makes a good shade tree. It is mildly deer-tolerant. Strong wood keeps this tree from suffering storm damage. USDA Plant Hardiness Zones 4 to 8.
Blackjack oak (Q. marilandica) is a small- to medium-sized tree usually topping out at between 15 to 45 feet, with an open, irregular, spreading crown of crooked branches and some dead twigs. It is a slow-growing and short-lived tree. Blackjack oak prefers average to dry, well-drained soils in full sun. It does not tolerate poorly drained soil. Blackjack oak is often found in areas where other trees will not grow because of the poor soil. This tree is rarely used in the home landscape but would be well-suited for a naturalized or woodland setting. USDA Plant Hardiness Zones 6 to 9.
Pin oak (Q. palustris) is a medium to large tree that grows 50 to 75 feet tall, with a somewhat conical crown. It has upright upper branches, horizontal middle branches, and its lower branches are pendulous – they angle downward. Pin oak prefers medium to wet, loamy, acidic soils and full sun. It can tolerate poorly drained soils and some flooding, but it is adaptable to drier as well as urban conditions. Pin oak does not tolerate alkaline soil. It is a shallow-rooted, easily transplanted, and fast-growing oak. USDA Plant Hardiness Zones 4 to 8.
Willow oak (Q. phellos) is a medium to large tree that grows to 140 feet, with a rounded crown and spur-like branches. Its leaves are long, narrow, and unlobed – closely resembling a willow tree and, hence, its common name. This oak is long-lived, grows rapidly, and is known for its heavy acorn production. It is native to the extreme southeastern corner of our state. This oak is easy to grow in acidic, average, medium-to-wet, and well-drained soils in full sun to light shade. It is adaptable to a variety of soil types, including clay soils. It is tolerant of urban pollution. Willow oak has a fibrous root system and transplants well. USDA Plant Hardiness Zones 5 to 9.
Northern red oak (Q. rubra) is a medium to large tree that grows to 75 feet, with a rounded crown and large branches. It is a fast-growing tree that transplants easily, often forming pure stands. The northern red oak prefers full sun, moist to dry, well-drained, acidic, fertile, sandy to loamy soils. Once established, it is drought, dry soil, black walnut, and air pollution tolerant. It can be used as a street tree. USDA Plant Hardiness Zones 4 to 8.
Shumard oak (Q. shumardii) is one of the largest of the southern red oaks, growing to 150 feet, with a large, round, open crown. It usually has a clear bole (a long, straight, branch-free trunk) with a buttressed base and shallow root system. It is tolerant of urban conditions such as drought, dry soil, and air pollution. Shumard oak is relatively fast-growing and adaptable. It also tolerates short-term flooding and wind. The lobed leaves often turn a nice red color in fall. Plant in average soil in full sun as a shade tree in a large yard, as a street tree, or in parks and other public places. USDA Plant Hardiness Zones 5 to 9.
Black oak (Q. velutina) is a medium to large tree, 50 to 110 feet in height, with an open and wide-spreading crown. This tree grows best in full sun and prefers moist, slightly acidic, well-drained, fertile soil. However, it is adaptable to soil types, including deep loam, clay, rocky material, or sand, and moist to dry conditions. It is tolerant of both drought and poor soils. USDA Plant Hardiness Zones 3 to 9.
