What is a Post Oak?

Post oak is a deciduous tree that is part of the Fagaceae, or beech family. It is native to the eastern half of the United States. This tree features an oval shape and a trunk that is gray or light reddish brown. It is commonly used as a shade tree or as an ornamental tree. The gypsy moth and the fungal disease oak wilt are two concerns to watch out for when growing the post oak.

Scientifically, the post oak is known as Quercus stellata. The genus name Quercus is derived from the Celtic words quer and cuez, which means "fine" and "tree," respectively. The species name, stellata, means "small star." Commonly, the post oak is also called the iron oak or the cross oak. In other regions, this tree is known as the delta post oak.

The post oak is distributed from Massachusetts to central Florida. It is also grown west to eastern Kansas and central Texas. This tree populates the dry and sandy ridges of the landscape, as well as prairies and limestone hills. It is also found in woodlands and deciduous forests.

This tree generally grows 40 to 50 feet (12 to 15 m) in height and spreads a similar width. The foliage consists of green leaves that are 3 to 5 inches (7.62 to 12.7 cm) in length. They have a wavy outline and feature several lobes. As the tree matures, it develops a thick, oval crown. The leaves change colors during the fall.

In early spring, the tree blooms yellow or pale green flowers. Afterward, the tree produces acorns that are light brown to black. They grow about 0.75 inch (1.9 cm) long.

Experts recommend this tree be grown in rocky or sandy soil that is acidic. Growing conditions are dramatically improved if the soil is well-draining. The area in which the tree is placed should have exposure to full sunlight. This tree is very drought resistant, and is a good choice for xeric landscapes.

Xeric landscapes, or xeriscapes, are landscapes which contain plants that only require natural rainfall to survive and don't require additional irrigation. This type of landscaping is ideal for drought-prone regions. The post oak fits well in this type of landscape; its acorns attract lots of wildlife, and it serves as a host for several butterflies.

A problem that affects this tree is oak wilt. This is a fungal disease that causes the leaves to turn yellow or brown. Affected trees should be pruned to reduce the chance of the fungus from spreading.