272 Halesia spp.Common Names: Carolina silverbells, silverbells, two-winged silverbells Family: Styracaceae (storax or silverbells Family)
The silverbells are wide-spreading shrubs or small trees with rounded crowns, rarely exceeding 30 ft (9.1 m) in height. Both species have deciduous leaves that are slightly toothed on the edges and pointed at the tips. The leaves of the two-winged silverbells (Halesia diptera) are 3-5 in (7.6-12.7 cm) long and almost as wide, whereas those of the Carolina silverbells (Halesia carolina) are a little smaller and relatively narrower. The leaves of both species turn yellow in fall. But it's the dainty white bell shaped flowers that hang from leafless branches in early spring that make these two natives stand out. The flowers of the Carolina silverbells are about 3/4 in (1.9 cm) long with the petals fused for about 3/4 of their length whereas those of the two-winged silverbells are about 1 in (2.5 cm) long, with petals joined for less than half their length. The curious fruits, a little more than 1 in (2.5 cm) long with two or four lengthwise "wings", dangle like little ornaments all summer and fall.
There are several named cultivars of Carolina silverbells, including some with pink flowers and some with variegated leaves. Halesia diptera var. magniflora is a naturally occurring variety of two-winged silverbells. It has larger blossoms that are about 1.5 in (3.8 cm) long and more abundant.
Both species of silverbells grow in rich mesic woods in floodplains and on the lower slopes of forested ravines. The Carolina silverbells occurs from West Virginia and Kentucky to Arkansas and south to northern Florida. The two-winged silverbells has a more southern distribution, occurring on the Coastal Plain from South Carolina to northern Florida and west to eastern Texas. Both are understory trees, tolerant of considerable shade and occasional flooding.
CultureOnce established, silverbells require little care. They won't need supplemental watering or fertilizing and they won't need spraying for pests or diseases. Silverbells do best in slightly acidic soils; do not add lime. Prune occasionally to maintain desired size and shape. Light: Full sun to shade. Moisture: Both species like well drained, but moist soils. Hardiness: USDA Zones 4 - 9. Carolina silverbells: USDA Zones 4-8; Two-winged silverbells: Zones 6-9. Propagation: The seeds of silverbells usually require two chilling seasons before they will break dormancy and germinate. The trees also can be propagated by layering and by stem and root cuttings.
Both species of silverbells make beautiful specimen trees in the dappled shade of a large live oak or on the edge of a woodland garden. Silverbells are dazzling when festooned with thousands of pendulant snowy white flowers, about the time the dogwoods finish blooming. They are, regrettably, more popular as ornamentals in Europe and the northern US than in their native southeastern United States. Choose two-winged silverbells for zones 7-9, and Carolina silverbells for zones 4-8. The large flowered variety of two-winged silverbells sometimes is available at native plant nurseries in Florida and other southeastern states.
The genus Halesia is one of several that illustrate the strong biogeographic connection between southeastern North America and eastern Asia. Like alligators, magnolias and azaleas, Halesia occurs naturally in both places, attesting to a former connection before the continents had drifted to their present positions.
Each spring I watch bright red cardinals perch among the snowy white silverbells and pull off petals one at a time only to drop them to the ground after rolling them around in their mouths for a few seconds. They must be getting a taste of sweet nectar. Hummingbirds visit the flowers too.
The experts are arguing over name changes for the Carolina silverbell. Dr. Dirr lists this species as Halesia tetraptera but we'll stick with Halesia carolina (which Dirr lists as a synonym) as this is how it is indicated by our chosen authority, the Institute for Systematic Botany which lists Halesia tetraptera as the synonym. (Just in case anyone cares...).
Steve Christman 06/20/97; updated 3/8/00, 4/8/04, 4/5/08