Beautiful in open woodlands or as a shade tree in a park, the eastern redbud (Cercis canadensis) boasts the title of being Oklahoma's state tree. It grows to 20 to 30 feet tall with a flat-topped, vase-like shape. Choose the Texan variety of the eastern redbud for gardens with alkaline or drier soils. Only in the eastern counties does the eastern redbud truly grow at its finest.
The redbud is native to the eastern half of Oklahoma. The original native range does not include extreme western or northwestern reaches of the state, including the Panhandle.
The redbud comprises three subspecies: the eastern redbud (Cercis canadensis var. canadensis), the Texas redbud (Cercis canadensis var. texensis) and the Mexican redbud (Cercis canadensis var. mexicana). The third does not grow in Oklahoma. The Texas redbud occurs in the limestone soils of Oklahoma's southern mountains and the eastern redbud naturally grows in the rest of eastern Oklahoma.
Fast growing when young, the eastern redbud's brown twigs display clusters of violet-pink flowers in early spring before the heart-shaped leaves emerge. Pollinated by insects, flowers become long and flat seed pods that ripen dark-brown and persist on the tree after the foliage turns yellow and drops away in autumn.
While both adaptable to soils and light exposures, the eastern redbud grows best in moist, fertile soils that are slightly acidic to slightly alkaline (pH 6.0 to 7.5). Avoid coarse sandy soils and those that flood. It handles full sun exposures well, over eight hours of direct sun daily, but in the hot summer climates of Oklahoma, partial shading maintains nicer foliage. About six to eight hours of direct sunlight daily suffices and shade on the foliage in the heat of the summer afternoon is best. As long as soil remains evenly moist, more heat and sunlight is tolerated. In the drier, more alkaline soils of central and western Oklahoma, the eastern redbud loses selection favor to the more resilient Texas redbud.
A cultivated variety, or cultivar, of the Texas redbud exists with the name "Oklahoma". Commonly called the Oklahoma redbud, it causes confusion since the eastern redbud is the state tree and more than two subspecies of redbud occur naturally in Oklahoma. Cultivar Oklahoma derives from the Texas redbud and thus the botanical name reads: Cercis canadensis var. texensis "Oklahoma." It differs from the eastern redbud in having slightly deeper rosy magenta flowers and glossier foliage with wavy edges.