|By William J. Sheick
Professor, University of Texas at Austin
During early-summer trips to the Gulf coast it is hard to miss the flashy red-flowering spears of coral bean (Erythrina herbacae). Lucky visitors to the coastal dunes might also glimpse coral bean’s smaller and rarer relative, the yellow-flowered necklace pod (Sophora tomentosa). Both of these wild legumes, so enticing to ruby-throated hummingbirds, can add special texture and color to a garden or patio.
The fact that coral (or Cherokee) bean grows wild as far north as the Red River suggests its suitability for most Texas gardens. Since this native spreads as wide as 4 to 6 feet and can reach much higher, landscape location is a consideration. This woody shrub looks best in its own space or in a garden background, especially along a fence or wall. (Erythrina x bidwillii is a 2-to-6 foot high hybrid for smaller spaces.) Although it prefers sandy conditions, coral bean actually thrives in many types of soil provided drainage is excellent. It does well in part-shade, but blooms best in full sun. The performance of this drought-tolerant perennial, which transplants easily, is enhanced by periodic watering and a light annual feeding.
In zone 9, where coral bean tends to be evergreen, plant size will be greater and pods produced sooner than in the northern regions of our state. Where it is evergreen, Coral bean should be pruned only when necessary and only after its display of pods, usually in late autumn. In locales where coral bean dies back in winter, prune with caution to avoid removing any new growth, which will bear next year’s blooms. Where the plant dies to the ground, remove the unsightly dead canes so that this legume can re-sprout with ease in the spring.
Depending on the region, red flowers appear in the spring or summer, followed by drooping green pods with white beans that turn deep scarlet. Unfortunately these attractive fruits are somewhat toxic, a fact to be kept in mind concerning children and pets. Generally the seeds in these pods do not germinate without scarification, and so semi-hardwood cuttings and especially root division offer more certain methods of propagation. Coral bean’s only pests of consequence are deer, undeterred by the plant’s short spines. On the other hand, visiting bees, butterflies and birds enhance the garden value of this attractive shrub.
A sprawling, leggy plant growing 3 to 6 feet high, necklace pod offers appealing silvery-green leaves, fuzzy to the touch, and racemes of brilliant yellow flowers. It produces striking pods similar to two other Sophora kin, Eve’s necklace and Texas mountain laurel. Due to compression points between seeds, these fuzzy thin pods look like 3-to-8 inch necklaces.
Also known as silver-bush and Tambalisa, necklace pod shares most of coral bean’s preferences: part to full sun, well-draining soil of various kinds, maintenance watering for optimal appearance, and a light annual feeding. Like coral bean, it is evergreen in warmer regions, tolerates droughts, flowers and fruits from spring through autumn, produces spines, bears pendant furry pods, propagates from scarified toxic seed, and attracts winged wildlife. It is also pest free, except for the caterpillars of sulphur butterflies.
Besides smaller size, looser structure and reported deer resistance, the biggest difference between these two floral cousins is necklace pod’s vulnerability to cold even in its coastal habitat. As a zone 9 shrub, it should be treated farther north as an annual or container plant. Where it can be planted outdoors, silver-bush is best tucked in among other plants to compensate for its asymmetry. Whether in such a setting or in a container, however, necklace pod’s bright yellow flowers are delightfully flamboyant.
Actual coral bean and necklace pod plants, rather than more commonly marketed seeds, are available from:
1371 Fayetteville Drive
Spring Hill, FL 34609
For propagation advice, consult Jill Nokes’s How to Grow Native Plants of Texas and the Southwest (Austin: University of Texas Press, 2001).