Over 10 types of redbuds grow in the United States. The most common variety is the Eastern redbud. While the others are less cold hardy and grow across USDA hardiness zones 6 through 9, the Eastern redbud grows well in zones 4 through 9. They all share certain characteristics, but for simplification, this article focuses on the Eastern redbud.
The Eastern redbud is a short-lived tree, relatively speaking, with an average lifespan of 20 years. In rare cases, they survive to 30 years of age. Because of this short lifespan, they tend to grow rapidly during the early years. The tree spreads to an average width of about 15 feet. They form a "V," or vase, shape if grown in the open, but may take on a more unusual shape if grown in a forest setting.
The redbud is known for its pinkish-purple flowers that may cover the trunk as well as branches. Most trees do not begin to produce these flowers until they are 7 years old. Buds begin to emerge once temperatures average about 50 degrees F for 30 consecutive days, usually in late March to early April across the United States. Flowers are bisexual and self-pollinating.
Redbuds have easily identifiable, heart-shaped leaves that emerge as the flowers are beginning to fade in early to late April. The tree is deciduous, turning yellow before shedding its leaves in the fall. The leaf grows to about 4 inches in length when mature. The leaves are simple and emerge in a zigzag growth pattern.
Trunk and Branch Growth
Redbuds can be trained and trimmed to grow on a single trunk, but will naturally grow on several trunks. They spread out widely and will tend to lean as they get older. Stem and twigs have a zigzag growth pattern. As younger trees, the bark will appear reddish-brown to dark brown. As the redbud ages, the dark brown bark begins to exfoliate, and an orange inner bark is revealed, giving the tree another ornamental feature.
Optimal growing conditions for the redbud include rich, well-drained soil, though it will adapt to most soil types. The redbud is somewhat shade-tolerant. but less so as it ages. The multi-trunk nature of the tree gives it smaller, thinner trunks that grow at angles as it spreads, the redbud is susceptible to wind damage. It should be planted in a location protected from wind, to allow the best growth potential.