90 Quercus nigraCommon Names: water oak, spotted oak, possum oak Family: Fagaceae (beech Family)
Water oak is a medium sized tree usually getting 50-80 ft (15-24 m) tall with a trunk 2-3 ft (60-100 cm) in diameter. Water oak develops a broad, rounded, symmetrical crown. The small, spatula shaped leaves show great variability in shape and often persist into the winter. The bark is smooth on young trees, grayish brown, turning blackish and scaly ridged on older trees. The acorns are about 0.3-0.7 in (0.8-1.8 cm) long, broadest near the base, and with a shallow saucer shaped cup that encloses only the base of the nut.
Quercus nigra occurs on the southeastern Piedmont and Coastal Plain from southern New Jersey, south to central Florida, and west to East Texas. Water oak is found along streams, on the margins of swamps, in bottomlands, and in all but the driest soils on upland sites. Despite its name, water oak is not particularly adapted to wet sites, and does not tolerate constantly wet soils. This is a weedy species, rapidly colonizing disturbed areas and frequently found in residential lots and lawns as well as fallow farmland, roadsides, and parks.
CultureLight: Water oak grows best in full sun, but is often relegated to partly sunny spots. Moisture: Water oak grows best in moderately moist, well drained soils. It does not tolerate prolonged flooding or soggy soils, nor does it persist in loose, sandy, exceptionally well drained soils. Hardiness: USDA Zones 7 - 10. Propagation: Acorns take two years to mature. Sow outside in fall for spring germination.
Water oak grows rapidly and matures quickly, reaching senility and beginning to fall apart in 40-70 years or less. Trees more than 2 ft (60 cm) in diameter at breast height are often rotten in the center and may be partially hollow. In the southeastern U.S., water oak and the very similar laurel oak (Quercus hemisphaerica), are the tree species most responsible for falling on homes, crushing cars, blocking roads, and dropping limbs through roofs. If you have a water oak more than a 2 ft (60 cm) in diameter with parts hanging over your house, you should have it removed or at least trimmed back. There are plenty of better shade trees. Water oak has been used as fuel and, in the absence of better wood, as a source of timber for light construction.
Water oaks are especially valuable to wildlife precisely because they begin to decompose and die so young. Woodpeckers, lizards, songbirds, hawks and other predators take advantage of the beetles, caterpillars, and other insects that invariably infest mature water oaks.
Because of its rapid growth, water oak is often used as a street and shade tree in many southern cities. But because of its tendency to fall apart, it's hard to recommend this practice.
Water oak is susceptible to trunk cankers and heart rot which can cause it to break off limbs and split its trunk as it becomes mature. Those with suitable sites and more patience would be better served by other oaks, such as live oak (Quercus virginiana).
Steve Christman 05/10/97; updated 07/14/07