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Carolina Silverbell

Halesia tetraptera (H. carolina)

Storax Family (Styracaceae)

Introduction: Carolina silverbell is a good small tree for shrub or woodland borders. It may have a rounded, pyramidal or vase-shaped habit. Its white, bell-shaped flowers bloom in April and May and are best seen from below the tree as they hang on pendulous stalks. Carolina silverbell is pest resistant.

Culture: This tree likes rich, well-drained, moist soil that is acidic (pH of 5 to 6). It becomes chlorotic in soils with high pH. Carolina silverbell grows best in soil with high organic matter content. It is an understory tree that requires a protected environment. It grows best in a collection of trees as it needs light shade. It is hardy in Zones 4 to 8. This tree is resistant to pests unless it is located on a droughty site in an alkaline soil. It will not survive those conditions. In addition, scale can be a problem when the tree is stressed.

Botanical Information

Native habitat: West Virginia to Florida to eastern Oklahoma. Growth habit: Low-branched with ascending branches, or spreading branches that form a wide, rounded crown.
Tree size: Height ranges from 30 to 40 feet, with a spread of 20 to 35 feet.
Flowers and fruit: Flowers are bell-shaped and white, or occasionally pale rose. Carolina silverbell flowers on year-old wood. Flowers are ½ to 3/4 of an inch long and are borne on pendulous stalks in clusters of two to five. They have yellow anthers that hang down like a clapper. The tree flowers in April to early May. Fruit is a star-shaped, dry drupe with four wings. It is 1½ inches long and green before turning light brown. It persists until the following year.
Leaf: Leaves are simple and alternate, 2 to 5 inches long. They are dark yellowish green in summer, and yellow or yellowish green in fall. Leaves usually drop in early fall.
Hardiness: Winter hardy to USDA Zone 4.

Related species: Mountain silverbell (Halesia monticola) had been considered its own species , but recently it has been grouped with Halesia carolina into a single genus as Halesia tetraptera. It is very similar to Carolina silverbell but it is larger, often reaching a height of 60 to 80 feet. It often has a conical habit. The cultivar ‘Rosea' has light pink flowers. Mountain silverbell, which was introduced into the landscape in 1897, may also be listed as H. monticola. This tree has thin bark that separates into long, reddish brown plates. It is native to mountains with elevations of at least 3,000 feet in North Carolina, Georgia and Tennessee. Mountain silverbell is among such species as sugar maple, Canadian hemlock, chestnut oak, black walnut, white ash and cucumbertree that dominate cool coves of the southern Appalachians. Mountain silverbells as much as 100 feet tall with trunks up to 4 feet in diameter have been found in the wild.

Additional information: Carolina silverbell is especially attractive when set off against an evergreen background. Rhododendrons grow well under the tree. This tree has grayish green to brownish black bark with long, buff-colored streaks. The bark is rough with ridges in older trees. Stems often peel and become "stringy." Carolina silverbell was introduced into the landscape in 1756.