Quercus incana aka Bluejack Oak

Quercus incana, or bluejack oak, belongs to the oak family, Fagaceae. Other names include cinnamon oak, sandjack oak, and shin oak. It grows wild across the Atlantic and Gulf coastal plains. Its range runs from Virginia through Florida and west to Texas. It also reaches inland into Oklahoma and Arkansas. In North Carolina, it grows in coastal and Piedmont areas. Its habitats include sandy barrens, ridges, and shaded woods.

This deciduous oak forms thickets as a shrub or small tree. Shrubs can reach 20 feet (6.1 metres) in height. NC State gives a tree range of 30–55 feet (9.1–16.8 metres). Virginia Tech describes smaller plants, reaching about 30 feet (9.1 metres). A short trunk carries bent branches and a loose, uneven crown. Virginia Tech also notes that many branches may be dead. The bark is black. Young brown twigs have hairs and five distinct angles. As the twigs age, they darken and lose their hairs. Reddish-brown buds cluster near the ends of branches.

The glossy leaves have a blue-green cast and remain into winter. Each leaf measures about two to four inches long. This foliage gives the plant much of its garden appeal. Yellow flowers appear in spring. The small acorns have caps made of scales. They take two years to develop. NC State lists the plant as a food source for wildlife. Its landscape tags also identify it as a caterpillar host. Birds, small mammals, butterflies, and moths add to its wildlife value.

Grow bluejack oak in full sun or some shade. It prefers acid soil with good drainage. Sandy soil and loam suit it well. NC State also lists tolerance of dry soil. Its native sandy sites help explain this preference for free drainage. Use it for shade or in a naturalized planting. It also suits coastal landscapes, where its loose shape fits informal settings.

Many insects and diseases can affect this oak. Even so, NC State says damage seldom becomes serious. Diseases include oak wilt, anthracnose, cankers, leaf spots, and powdery mildew. Oak leaf blister can also occur. Insect pests include scales, aphids, leaf miners, and lace bugs. Several moth caterpillars also feed on it. NC State flags low-severity poisoning and a risk to horses. The supplied species evidence does not establish safe human food use.