Carolina Silverbell

(Styracaceae - Storax Family)

Form

• medium-sized ornamental tree
• maturing at about 30' tall by 20' wide under urban conditions, but up to 60' tall in the wild
• upright irregular growth habit (either single-trunked and low-branched, or multi-trunked, with ascending branches forming an irregular canopy that is highly variable from one tree to the next)
• medium growth rate

Culture

• full sun to partial shade
• prefers partial sun to partial shade in moist, acidic, well-drained, organically-enriched soils; it is not urban tolerant, especially to heat, drought, and poor soils, and may develop chorotic foliage when placed in alkaline pH soils
• propagated by rooted stem cuttings or by seeds
• Storax Family, with no serious diseases or pests
• moderately available, primarily in ball and burlap form

Foliage

• medium green, alternate, ovate to elliptical, and serrulate
• fall color is chartreuse to yellow-brown, and not at all ornamentally effective

Flowers

• white, in late April or early May, as pendulous bell-shaped clusters of flowers on short pedicels from the previous year's wood, with each flower consisting of four fused petals, with the flowers persistent for about a week
• very attractive when viewed from a short distance, but best viewed by looking up into the canopy or at eye-level to achieve the maximum ornamental effect, since they are pendulous, emerge with the foliage, and are therfore slightly hidden

Fruits

• lime green, distinctly four-winged, changing to brown, and usually abscising in Autumn, but with a few fruits persistent into the following Spring

Twigs

• tan and pubescent at the end of the first growing season, becoming darker brown then gray in the second year, developing stringy exfoliating filaments on the second- and third-year wood
• young branches remain smooth and brown-gray, with prominent darker striations

Trunk

• older branches and young trunks become furrowed, flat-ridged, and blocky, while mature trunks are more deeply fissured and dark gray, sometimes mottled with a lighter brown coloration

ID Summary

• pendulous bell-shaped white flowers in Spring, lime-green four-sided immature fruits in Summer, thready second- and third-year stems, and prominently striated young branches give this irregularly-shaped native understory tree several unique identification traits

USAGE

Function

• specimen tree for the border, woodland edge, understory, or even foundation site, as long as the proper soil, moisture, and drainage conditions are met

Texture

• medium texture in foliage and when bare
• average density in foliage and when bare

Assets

• white bell-shaped flowers in Spring
• striated to furrowed gray-brown bark
• lime-green, four-sided fruits in late Summer
• shade tolerant

Liabilities

• irregular and somewhat unpredictable in growth habit, although generally upright
• poor fall color

Habitat

• zones 4 to 8
• native to the Eastern United States

SELECTIONS

Alternates

• mid-Spring flowering trees (Cornus florida, Crataegus viridis 'Winter King', Malus, etc.)
• small- to medium-sized trees with subtle stem/branch/bark ornamental character (Amelanchier laevis, Cornus florida, Crataegus viridis 'Winter King', etc.)
• native understory ornamental trees or large shrubs (Aesculus glabra, Amelanchier canadensis, Carpinus caroliniana, Cercis canadensis, Ostrya virginiana, Viburnum prunifolium, etc.)
• trees with oddly-shaped fruits (Asimina triloba, Carpinus betulus, Koelreuteria paniculata, Ostrya virginiana, Staphylea trifolia, etc.)

Variants

• straight species is the predominant form, although cultivars exist, including some with pinkish flowers

NOTES

Translation

• Halesia is named after Stephen Hales, an 18th century English scientist and inventor.
• tetraptera translates as "four winged", referring to the four wings on each fruit.
• formerly known as Halesia carolina, where the specific epithet translates as "from Carolina".

Purpose

• Carolina Silverbell is an alternative to Flowering Dogwood and some Crabapples as an ornamental tree with white mid-Spring flowers.

Summary

• Halesia tetraptera is known as a tree with prolific mid-Spring white bell-shaped pendulous flowers that is best sited in semi-shady locations with moist, rich soils.