Redbud trees belong to the pea family and like the rest of the members of the family, are susceptible to trunk canker, Verticillium wilt and scale insects. Gardeners in most of the country, with the exception of the coldest and hottest USDA zones, have a choice of at least one variety of redbud tree.
Eastern redbud (Cercis canadensis) is also known as the Judas Tree. It grows from 15 to 30 feet tall and about the same in width, starting out with a vase shape and developing a spreading crown as the plant matures. Give the tree full sun or partial shade and rich, moist, well-drained soil. Eastern redbud survives in dry soil, but not in wet. Medium-green, heart-shaped leaves grow to 4 inches long and 4 inches wide, turn dark green as they age and finally a chartreuse color in the fall. Clusters of small dark-brown buds turn purple-lavender as they grow and open to reveal pink-lavender flowers in the spring, covering the tree before the leaves put in their appearance. The flowers are followed by flat, green seed pods that turn brown, staying on the tree for as long as one year. Eastern redbud is hardy in USDA zones 4 to 9. The tree does not stand up well to the pollution in an urban setting, leading to a shortened lifespan of 10 to 20 years.
Chinese redbud (Cercis chinensis) is hardy in USDA zones 6 to 9 and grows from 8 to 15 feet tall with a crown spread of 6 to 12 feet. Give the plant full sun or partial shade and a soil that is average, moist and well drained. The tree produces an abundance of large clusters of rose-purple flowers in March and April, which is followed by heart-shaped leaves. Seed pods measure 5 inches long and appear in the late spring. Chinese redbud is one variety with more resistance to the typical disease of the pea family.
Mexican redbud (Cercis canadensis var. mexicana) is a small tree or large shrub that grows from 5 to 12 feet tall with glossy green leaves with wavy edges and red flowers that bloom in February, March and April. The flat seed pods grow to 4 inches long. Plant Mexican redbud in full sun or partial shade and dry soil. The tree is very drought tolerant. Bees and butterflies will stop by for a drink of the nectar. The tree is hardy in USDA zones 6 to 9.