The redbud tree (Cercis canadensis), also known as Eastern redbud or Judas tree, is the state tree of Oklahoma. In the United States, redbuds have a wide potential growing area, from upper Maine and Washington state down through large portions of Texas and Florida.
Redbuds are deciduous, single or multi-trunked, branching, twiggy trees with spreading, graceful canopies. The trees reach up to 40 feet tall, but are commonly seen 20 to 30 feet tall, with a 25- to 35-foot spread. Its green leaves are palmately veined, have a papery texture and are up to 6 inches across. Redbuds have thin, dark reddish-brown bark. Rosy-pink-, lavender-, or purple-colored ½-inch pea-like flowers bloom in spring. Redbuds produce 4-inch brown pods that remain on the tree after leaf fall.
Grow redbuds in full sun to partial shade, but they flower best in full sun sites. Redbuds benefit from partial shade in areas where summers are particularly hot. These trees prefer nutrient-rich, well-drained soils and are not salt-tolerant. Redbuds withstand hot, dry conditions and acid or alkaline soil, but not waterlogged conditions. They can be propagated by seeds, cuttings and grafting of cultivars. They are hardy in USDA Zones 4b through 9a.
Redbuds are good street trees, framing specimens or foundation trees. They are early-flowering trees in springtime, well suited to residential landscapes and naturalized areas and nice alone or in groups. The redbud grows rapidly when young and begins flowering after four to six years.
Cercis canadensis cv. Alba has white flowers and blooms slightly later. Purple Leaf has purple new foliage, Silver Cloud has white and green variegated leaves and Pinkbud has pure pink flowers. Cercis canadensis var. texensis Texas White and Cercis reniformis Oklahoma have superior foliage to Eastern redbud and are good substitutes, especially in non-irrigated areas, according to University of Florida extension.
Redbuds often have a short life of 10 to 20 years in urban settings; the bark is thin and easily damaged, and the wood is weak and tends to break. Canker is redbud's biggest disease problem and has no chemical control. Leaf spot disease and verticillium wilt also attack redbud. Pests include borers, chewing insects, webworms and scale insects. Your local county extension agent is a good source of information regarding the detection and management of pests and disease in your location.