Ask Mr. Smarty Plants

Mexican Buckeye (Ungnadia speciosa), an 8-12 ft., deciduous tree, can reach 30 ft. in height. It is often multi-trunked with with light gray to brown bark, smooth on young branches, becoming fissured with age. Leaves up to 12 inches long, with a central axis supporting 2 to 6 paired leaflets and a terminal one; leaflets up to 5 inches long, ovate to narrower with an elongate tip, rounded base, and serrate margins. Pinnate foliage turns golden yellow in fall. Clusters of bright-pink, fragrant flowers appear before or with the leaves from the axils of the previous season. Fruit distinctive, a light reddish brown when ripe, 3 lobed capsule containing 1 to 3 dark brown to black, shiny seeds 1/2 inch in diameter, the walls of the capsule often persisting through the winter, seeds poisonous.

From a distance the plants in full flower resemble redbuds or peaches. The sweetish but poisonous seeds are sometimes used by children as marbles. Livestock seldom browse the toxic foliage, but bees produce fragrant honey from the flowers. Although not a true buckeye, it is so called because of the similar large capsules and seeds. This distinct plant, alone in its genus, commemorates Baron Ferdinand von Ungnad, Austrian ambassador at Constantinople, who introduced the Horsechestnut into western Europe in 1576.

Mexican Buckeye is hardy to USDA zone 7 to 9. Greenville is at the northern edge of USDA zone 7b. So with protection it might survive. But be warned that it is at the edge of the reliable hardiness zone. If you can, create a microclimate for it by planting it on the south side of a building, fence or evergreen conifer. Mulch the plant well for the first several years to protect the roots. It may die down to the ground and then grow up again like a shrub.  Good luck.