Oak Species
 

Mature Size, Growth, Longevity

Most oaks are in the 40-100' tall & wide range. Some cultivars are narrow, upright, making a good screen, while others have stately, picturesque, wide-spreading branches w/ winter interest. Oaks are often moderate/slow growers, but some are faster growing. Generally long lived, 100-400 years.

Native Range

Many oaks are native to the U. S., while others have their origin in Europe, Asia or other parts of the world.

Flower and Fruit Details

Most oaks bloom in April, with non-ornamental, greenish-yellow male catkins and very small, reddish female flowers. The fruit of an oak is an acorn, made up of the nut and the cap, or cup, which may barely or mostly cover the nut. Caps are usually scaly. Acorns normally change from green to brown as they mature in the fall.

Leaf and Bark Features

Deciduous: Many oak leaves are lobed, but some have serrate margins, and others are more linear with entire margins. The white oak group generally has rounded lobes, while the red/black oak group generally has pointed lobes. Most oaks in the United States are deciduous. Since many oaks are grown from seed, tremendous variation occurs in their fall foliage color, so the best time to choose one at the nursery is in the fall. Fall color ranges from brown to golden yellow to red. Most oaks have gray to black bark, sometimes smooth in youth, but changing to flaky or ridged and furrowed.

Culture and Care

Iron chlorosis may be a problem with certain species of oaks on alkaline soils. Many oaks are drought tolerant, salt tolerant, cold & heat tolerant. Many oaks are hardy from Zone 4/5 to 8/9. Most oaks, like most trees/shrubs, prefer a slightly acid, well-drained, moist soil, but oaks as a group are very tolerant of adverse conditions, usually performing well in clay soils of various pH levels. Full sun is usually best. Oaks have many types of insect galls, various other insect and disease problems, including borers, caterpillars, scale, bacterial leaf scorch, anthracnose, canker, leaf spot, powdery mildew, gypsy moth, lacebugs and mites.

Strengths, Weaknesses, Other Facts

Good wildlife value. 3-season interest: Spring, summer and fall. Most oaks are strong wooded.

Suggested Uses

Oaks usually make good shade trees or specimen trees for home & business landscapes. The larger species are used heavily in parks and on larger estates. Fastigiate varieties may be used for screening.

Taxa and Plants of this Species at BCA