Halesia Diptera Two-Winged Silverbell

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Halesia diptera J. Ellis Two-Winged Silverbell (Carlomohria diptera, Mohria diptera, Mohrodendron dipterum)

Other Common Names: Cowlicks, Silver Bell, Snowbell, Snowdrop Tree, Two-Winged Silver Bell. Family: Styracaceae (Halesiaceae). Cold Hardiness: Trees are useful in USDA hardiness zones 7 to 9. Foliage: Alternate, deciduous, simple, 3O to 4O long, elliptic to obovate leaves have broadly acute, cuneate or nearly rounded bases, shallowly serrated margins, and acuminate tips; pinnate veins are lightly impressed above and raised beneath; new growth is pubescent, but this is largely lost as leaves mature; summer foliage is medium to dark green, while fall colors are yellow-green to yellow. Flower: Glistening white, inverted, elongated, bell-shaped, four-petal, perfect, pendent flowers hang beneath the previous season's twigs in numerous small clusters during spring; numerous yellow stamens hang in the flower with a single distended white pistil; flowers are particularly attractive when viewed from beneath. Fruit: Two-Winged Silverbell has a small, hard, dry, beaked drupe surrounded by a teardrop-shaped two- winged membrane that hangs by a slender peduncle approximately the length of the 2O long fruit; fruits progress from a bright fleshy green to mature a tan or light brown color; old fruit are often persist throughout the winter. Stem / Bark: Stems — young twigs are green maturing to gray-brown to brown; new twigs are slender becoming medium textured and lack the white streaks present on H. carolina; the spongy pith is sometimes chambered; Buds — the reddish brown lateral buds are elongated, ovoid, and slightly divergent; Bark — bark of young trees is shallowly fissured into smooth silvery elongated plates; older trunks become vertically ridged and furrowed, mildly scaly, and sometimes almost corky in old age, mature bark is red-brown to gray-brown in color. Habit: Halesia diptera grows into a single or multi-stem small tree with a rounded to upright oval crown eventually reaching 25N to 30N tall on favorable sites; trees are medium in overall texture. Cultural Requirements: As with most species of Halesia, a rich organic soil with good drainage and uniform moisture is required for strong growth; in nature H. diptera is a woodland edge tree often growing where it can receive shade during portions of the day; in more moderate climates it can be grown in full sun, the further west and south it is located the more it benefits from partial shade; growth rates are rather slow; plants should be transplanted from containers and need a little post- transplant tender loving care until fully established. Pathological Problems: Few pathological problems are reported other than a foliar fungus in hot moist environments. Ornamental Assets: Glistening white spring flowers are the primary asset, while yellow fall colors can be decent in milder climates; the flowers attract hummingbirds. Limitations & Liabilities: Like most Halesia, H. diptera is intolerant of hot dry sites, high pH soils, or salinity exposure; flowering occurs as leaves emerge and are located below them, sometimes resulting in the flowers being partially hidden. Landscape Utilization: Halesia diptera can be used as a substitute or companion plant for Cornus florida, thriving in similar environments, although it may require even more regular moisture regimes; locations adjacent to seating areas or along woodland paths where the flowers can be enjoyed looking up into the canopy show them to best effect; night lighting up into the canopy during spring bloom can be impressive. Other Comments: Halesia carolina is the more common plant in the upper south and has been utilized more extensively in cultivated landscapes than H. diptera, but H. carolina is native only In the Ozarks in our region; the genus name honors the English scientist, Reverend Stephen Hales, while the specific epithet means two-winged in reference to the seeds. Native Habitat: Two-Winged Diptera is native to bottomlands from East Texas across the Coastal Plain of the Southern USA and Gulf Coast. Related Taxa: 'Magniflora' has larger flowers than the species type and is sometimes treated as Halesia diptera var. magniflora; the genus Halesia J. Ellis ex L. is a small genus containing a handful of species from North America and Asia, although recently some authors have transferred the Asian species to a separate genus.

Halesia carolina L. Carolina Silverbell (Carlomohria carolina, Halesia monticola, Halesia parviflora, Halesia tetraptera, Mohrodendron carolinum) • This species is also known as Carolina Silver Bell, Florida Silverbell, Little Silverbell, Mountain Silverbell, Silverbell Tree, or Snowdrop Tree; Halesia carolina is native to the Eastern USA from the Northeastern states, through the Midwest, and to the Appalachian Mountains in the Southeast; it is a larger, often small tree size, version of H. carolina that offers similar flowers and sometimes good yellow fall color; generally speaking H. carolina is preferred in the Upper South, Northeast, and Lower Midwest, tolerating colder temperatures than H. diptera; Carolina Silverbell can be grown in USDA hardiness zones 5a- 8(9a), but it lacks vigor in the Deep South, where H. diptera should be used instead; nationally H. carolina is the more common of the Halesia found in the nursery trade, but is still by no means common; the specific epithet alludes to this species nativity in the Carolinas. • Halesia tetraptera is sometimes treated distinctly from H. carolina; it is known variously as Little Silverbell, Opossum-Wood, Shittum-Wood, or Wild Olive.

Styrax americanus J.B.A.P.M. de Lamarck Storax (Cyrta japonica) • Also known as American Snowbell, Mock Orange, Snowbell, Silverbells, or Styrax; this medium to large deciduous shrub, typically 6N to 9N tall, rarely reaches a 15N tree size; the simple, alternate, 1½O to 3O long leaves are elliptical to ovate and remind one of those of Halesia, but with short acute tips; twigs and new leaves are densely stellate-pubescent, with stems and upper surfaces loosing most of the pubescence at maturity; lateral buds lack bud scales; smooth dark gray bark develops at maturity; the perfect flowers are bell-shaped with five distinct pointed lobes; Halesia have four petals, whereas Styrax have five petals; the ½O long white flowers are borne in short, one to four- flowered racemes up to 3O in length; a densely pubescent globose ⅓O diameter drupe follows in fall. • Storax requires regular moisture and rich humusy soils similar to its moist woodland habitat in the Central USA and Southeastern USA Piedmont and Coastal Plain; it is found natively in East Texas, Louisiana and Arkansas in our region; Styrax americanus is limitedly available in native plant nurseries and should be considered for use in woodsy settings as a trailside shrub; Storax is useful in appropriate sites in USDA hardiness zones 6b to 9a (9b); the specific epithet refers to this species American origins. • Styrax grandifolius W. Aiton, Bigleaf Snowbell or Coast Snowbell, is a larger version of S. americanus suitable for similar uses as H. diptera and H. carolina; it has leaves about twice the size of those of S. americanus, 3O to 6O long, is often a large shrub or small tree that can reach 20N, and offers longer 5O to 6O long racemes bearing five to twenty perfect white flowers in early spring; it is useful in woodsy settings in USDA hardiness zones 7b to 9a; it is encountered in East Texas, Louisiana, and Arkansas in our region; the specific epithet refers to its large leaves relative to other species in the genus Styrax. • Styrax japonicus P.F. von Siebold & J.G. Zuccarini (Cyrta japonica, Styrax bodinieri, Styrax grandiflorus, Styrax kotoensis, Styrax seminatus), Japanese Snowbell, Japanese Storax or Japanese Styrax, is a larger version of S. americanus reaching 25N to 30N tall and has larger flowers than S. americanus; it fairs poorly in the heat of the Deep South and is best adapted to USDA hardiness zones 6b (6a) to 8; the specific epithet refers to this species' origins in Japan.

References: Cox and Leslie, 1988; Duncan and Duncan, 1988; Flint, 1997; Gill and White, 2002; Kirkman et al., 2007; Odenwald and Turner, 1996; Simpson, 1988.