Carolina Silverbell (Halesia carolina)

Carolina Silverbell, Common Silverbell, Mountain Silverbell, Opossum wood, shittimwood, Silver Bell, Snowbell tree

With its showy silvery flowers Carolina Silverbells, Halesia carolina, creates a show-stopping display in spring. Bells of white bloom in spring before leaves appear. This open-form tree grows into a loose pyramidal shape, slowly to 20-30′ tall and wide. A lover of acidic soils and part shade, Carolina Silverbells is a perfect choice planted with Azaleas, Hydrangeas and other acid-loving shrubs.

I. Appearance and Characteristics 

Halesia carolina, commonly called Carolina silverbells or little silverbells, is a species of flowering plant in the family Styracaceae, native to the southeastern United States.

It is a vigorous, fast-growing deciduous shrub or tree growing to 8 m (26 ft) tall by 10 m (33 ft) broad, bearing masses of pendant, bell-shaped white flowers which appear in spring before the leaves. The flowers are followed by green, four-winged fruit. The leaves turn yellow in autumn.

In cultivation in the United Kingdom, H. carolina Vestita Group has gained the Royal Horticultural Society’s Award of Garden Merit. It requires an acid or neutral soil, in a partially shaded position.

The fruits may be collected in late fall and early winter.

The range of little silverbells is very restricted. It is principally in the panhandle of Florida, with isolated smaller outlier populations in South Carolina, Georgia, Alabama, Mississippi. In the cited reference, this species is referred to as Halesia parviflora. The “champion” Halesia Carolina on the 2015 American Forests’ National Register of Champion Trees is quite removed from its natural range, being situated in Roxbury, New Hampshire.

There is a great deal of confusion in the four-winged American silverbells. Four principal species names have been used: H. carolina, H. parviflora, H. monticola, and H. tetraptera. The taxon being described here is the one that has also been described as H. parviflora. Some botanists have discarded the name H. carolina because the original material is viewed as ambiguous; others maintain that the original material is this species, so carolina is here being used instead of parviflora, since H. carolina L. has clear precedence.

II. How to Grow and Care

Behind its delicate appearance, Carolina silverbell is actually a fairly hardy, easy-to-grow spring plant that bridges the gap between a shrub and a tree and is appealing both when flowering and throughout the rest of the season. It’s usually planted from container-grown specimens (found at a nursery or garden center) because seeds take a long time to germinate.

When it comes to caring for the Carolina silverbell, it has few requirements beyond a slightly acidic soil pH level; accomplish that (and provide it with enough sunlight) and you’re almost guaranteed to have a happy plant that will enliven your landscape for years to come. Additionally, the plant has no serious pest or disease issues.

Sunlight

As an understory tree, Carolina silverbell grows best in a partially sunny spot, though it can also tolerate full sunlight. Your best bet is to find a place in your landscape that receives full sun in the morning but partial shade in the hotter afternoon hours so that the plant can soak in the necessary sunlight (about six hours daily is best) without burning.

Temperature and Humidity

Carolina silverbell’s native habitat is the moist, protected forests of the lower Appalachian Mountains, so it will do best in an environment that mimics those conditions. Extreme heat and dryness stress the plant especially when it is young.

Watering

To keep your Carolina silverbell happy, maintain consistently moist soil conditions. If you live in a particularly dry environment, it might be wise to set up an irrigation system, especially when the tree is young. Once established, your Carolina silverbell will be moderately tolerant of drought.

Soil

Carolina silverbell prefers organically rich, medium-moisture, well-drained soil that is somewhat acidic—it grows well in conditions similar to those that azaleas and rhododendrons love. If the soil in your landscape is not acidic enough (a pH level around 6.5 is best), you can amend the soil to create the proper environment.

Fertilizing

Feed your Carolina silverbell with an organic fertilizer at planting time and then again each spring until the tree is fully established. For the amount to use, follow the product label instructions. When the plant is established, supplemental feeding is not necessary.

Planting Instructions

Plant Carolina silverbell in the filtered shade of widely spaced mature trees, where the dappled sunlight will provide just enough of the sun’s energy to bloom profusely without burning the foliage. The flowers are best viewed from below, so this convenience should play a role in siting. Choose a container grown specimen and amend the soil to ensure a rich, acidic, well drained situation. Add plenty of organic matter to the planting hole, and mulch well to provide consistency of soil moisture.

Pruning

This plant can form multiple trunks, so choosing one as a central leader when it is in its early years and pruning away the lower branches will train it into a tree form. As with any tree or shrub, damaged or diseased branches should be removed.

Propagation

Cuttings 

You can propagate new Carolina silverbell plants by taking softwood cuttings with the best time to do so being early June. Here’s how:

  • With clean, sharp pruners, cut a four- to six-inch stem tip just below a growth node. Remove the leaves from the bottom half of the cutting.
  • Treat the cut end of branch cuttings with a rooting hormone, then plant them cut-side down in pots filled with growing medium.
  • Enclose the cuttings inside a plastic bag to increase humidity.
  • Set the pot in a bright location but out of direct sunlight. Keep the soil evenly moist.
  • When roots develop (tug lightly on the stem; if you feel resistance, roots are present), you can transplant the cutting into a larger container. Cuttings can be planted in the landscape the following spring.

Seed

Propagation by seed is possible and it is best to gather seeds in the fall from a mature tree. Harvest around five to ten mature seedpods that do not have any physical signs of damage. Soak the seeds in sulfuric acid for eight hours followed by 21 hours of soaking in water. Wipe away deteriorated pieces from the pods.

Mix 2 parts compost with 2 parts potting soil and 1 part sand, and place into a flat or large pot. Plant the seeds about 2 inches (5 cm.) deep and cover with soil. Then cover the top of each pot or flat with mulch.

Water until moist and keep the soil moist at all times. Germination can take as long as two years.

Rotate every two to three months between warm (70-80 F./21-27 C.) and cold (35 -42 F./2-6 C.) temperatures.

Choose a suitable location to plant your tree after the second year and provide an organic fertilizer when you plant and each spring thereafter as part of your Halesia tree care until it is well established.

Pests and Diseases

  • Common Pests and Plant Diseases

Carolina silverbell is quite resistant to pests. It can develop scale if the tree is stressed, dealing with drought, or if the soil pH is too alkaline.

  • Common Problems With Carolina Silverbell

The only puzzling problem some gardeners might have with Carolina silverbell is a yellowing of the leaves. This can usually be attributed to chlorosis, which occurs as a result of growing in soil that is too alkaline (soil pH is too high). Amending the soil to make it more acidic is necessary to ensure the best health for your Carolina silverbell.

Overwintering

When planted in the proper USDA hardiness zones, Carolina silverbell doesn’t need any particular winter protection. For young trees, several inches of mulch spread over the root zone out to the drip line can provide protection.

Maintenance

If the native soil is of a high pH, use aluminum sulfate periodically to bring it down below 6.5. Always check pH before treatment.

III. Types of Carolina Silverbell

There are several different varieties of Carolina silverbells, with most differences being in the color or size of the flowers.

  • · For pink flowers, plant ‘Rosy Ridge’, ‘Rosa’, or ‘Arnold Pink’.
  • · If you like variegated leaves, look for ‘Silver Splash’ or ‘Variegata’ .
  • · ‘Wedding Bells’ produces larger and numerous white flowers.

IV. Uses and Benefits 

  • Ornamental uses

Carolina silverbell is a deciduous tree or large shrub that bears white bell-shaped flowers in early spring. The plant naturally forms a rounded crown with multiple stems and can be grown that way as a large shrub or it can be trained into a single-trunk tree by removing all but one central leader trunk. It’s a good choice for woodland borders or as a specimen lawn tree—rhododendron shrubs are often planted happily beneath its canopy.

  • Other uses

Carolina silverbell is known as bellwood or tisswood in the craft trades. The wood is soft with white sapwood and reddish heartwood that may be marked with white streaks. The lumber value is not of great economic importance, however wildlife hold the tree in higher regard. Squirrels love the ripe fruits, and use the tree for nesting. Bees frequent the blooms for nectar while in season.

Carolina Silverbell (Halesia carolina) Details

Common name Carolina Silverbell, Common Silverbell, Mountain Silverbell, Opossum wood, shittimwood, Silver Bell, Snowbell tree
Botanical name Halesia carolina
Plant type Native Plant
Hardiness zone 4a, 4b, 5a, 5b, 6a, 6b, 7a, 7b, 8a, 8b
Growth rate Medium
Harvest time Fall
Height 10 ft. 0 in. - 40 ft. 0 in.
Width 10 ft. 0 in. - 40 ft. 0 in.
Sunlight Dappled Sunlight (Shade through upper canopy all day)
Soil condition High Organic Matter
Flower color Pink
Leaf color Gold/Yellow