The fact that this plant is beautiful is unchallenged. Its attractiveness to hummingbirds and butterflies is well documented. However, its beans are very poisonous. The leaves and stems have prickles, and sharp, recurved spines arm the stems. Decide for yourself whether or not the coral bean would be a good addition to your landscape.
All of us have those places in our gardens-places where the soil is poor or where the irrigation system does not reach. It is for these places that we choose tough, native plants. If wisely chosen and given some modicum of care during the establishment period, such plants will flourish with little or no supplemental irrigation. They often need no fertilizer, and no chemicals will be needed to control insect pests.
The showy coral bean (Erythrina herbacea) is one example of a native plant that will survive in an out-of-the-way place in the landscape with very little effort on the gardener's part. Sometimes called Cherokee bean or cardinal spear, this native legume grows naturally in hardwood hammocks throughout the southern portions of the United States and on into Mexico. Most references place it in USDA Zones 8-10, but there is some evidence that it can be successfully grown somewhat beyond this range.
In spring, clusters of bright red tubular flowers up to two inches long are held on leafless spikes well above the foliage. Later in the season, its membership in the Leguminosae family (now Papilionaceae subfamily) is evident when large bean-like pods appear. These pods split open in fall to reveal bright red seeds that stay attached to the pods for a few weeks.
Not only are the flowers and beans attractive; the foliage lends its own kind of beauty. Bright green, compound leaves are uniquely shaped. Each leaf contains three leaflets that are broad in the center but pointed at the tips. Be careful as you work around this plant, because it is well armed. Along the midribs on the underside of each leaf are stickery prickles, and the stems are armed with short, recurved spines capable of grasping unsuspecting ungloved hands.
Growing Coral Bean
If you decide that you want a coral bean in your landscape, choose a place with well-drained soil and some protection from the hot, afternoon sun. Consider its accessibility to children who may be tempted to try the beautiful red, but highly toxic beans. Also, think about whether or not visitors to your garden will brush against the shrub and be caught by its spines.
Another consideration that is seldom considered when deciding where to place plants is whether or not they can be transplanted easily. The woody root of the coral bean is massive and difficult to dig after it has been in place for a while. Be sure to plant it where you want it to stay. Know that if you do have to dig it at some time in the future, you will have a sizeable job on your hands.
Coral bean is easily propagated by seeds or cuttings. Seeds that fall on the ground sprout readily. As you might expect, birds carry them far from their point of origin, so new plants might sprout in places where you don't want them.
Coral bean is drought-tolerant as well as moderately salt-tolerant. Frost or freezing weather will kill it back to the ground, but it reemerges each spring. Although the plant prefers rich, organic soil, it is tolerant of much less and does satisfactorily on sandy, well-drained soil in full sun or partial shade. Cut back the dead limbs from the previous summer's growth just before new growth emerges. Give it a shot of fertilizer while you're at it if you want to stimulate more vigorous growth. Expect coral bean to grow about 20 feet tall if you live in a frost-free area. In places where cold weather kills it back, it seldom grows taller than 8 feet.
Uses of Coral Bean
Coral bean is a popular choice for hummingbird and butterfly gardens. The tubular flowers seem made-to-order for hummers' tongues. The roots were once used by Native Americans to increase perspiration, and the beans have been used as rat poison and to paralyze fish. Young flowers and leaves can be safely cooked and eaten, but ingesting the seeds may cause diarrhea and vomiting.