Tree Description
Water oaks are large trees growing to 90 feet in height with trunks up to 3 feet in diameter. They have dense, round crowns of dark green foliage.
Range / Site Description
The trees occur along the borders of swamps and streams and on rich bottomlands in East Texas, extending west and south to the Colorado River.
Leaf
The leaves are simple and alternate, 2” to 4” long and 1” to 2” wide, its shape either obovate or three-lobed at the outer end. The leaf’s upper surface is dull bluish-green in color, and its lower surface is lighter green. The leaves persist on the twigs late into winter. Juvenile leaves are highly variable and have a mix of sharp teeth and rounded lobes.
Flower & Fruit
Separate male and female flowers appear on the same tree in spring when leaves begin to unfold. Male flowers are borne on a yellowish catkin, 2” to 3” inches long; female flowers are less conspicuous and clustered on a short stalk.
The fruit is an acorn, ½” to ¾”long and wide, light brown or yellowish brown in color, and enclosed only at the base in a thin, saucer-shaped cup. It requires two years to mature.
Interesting Facts
Along with several other oaks, water oak is commonly referred to as “pin oak” because of its similarities to the true pin oak (Quercus palustris), except for leaf shape. This name is almost generic for any unknown oak species.
Species Summary
| Scientific Name: | Quercus nigra |
| Secondary Names: | Pin Oak |
| Tree Type: | Deciduous |
| Dimensions: | Height: 90 feet Trunk Diameter: 3 feet |
| Leaf Structure: | Simple, alternate |
| Leaf Size: | 2-4 inches long and 1-2 inches wide |
| Leaf Shape: | Obovate or three-lobed at the outer end |
| Leaf Margin: | Variable, smooth to shallowly lobed |
| Additional Information: | iNaturalist – Water Oak |
Source: Texas A&M Forest Service Trees of Texas – Water Oak