Noted for its showy cinnamon-colored bark and fragrant white flowers, Clethra acuminata (Cinnamon Clethra) is a small, multi-stemmed, deciduous shrub or handsome small tree with an elegant tiered branching habit. Clethra acuminata can reach as high as 6 m tall. It has acuminate leaves with teeth along the margins, and solitary white flowers.Â
I. Appearance and CharacteristicsÂ
Clethra acuminata, the mountain pepper bush, is a shrub native to the Appalachian Mountains of the southeastern United States. It has been reported from the states of Pennsylvania, West Virginia, Virginia, North Carolina, South Carolina, Georgia, Alabama and Tennessee, primarily from deciduous forests at elevations of 500–1,400 m (1,600–4,600 ft).
Clethra acuminata was discovered and named by French botanist Andre Michaux in his work The Flora Boreali published in 1829-1840.
Clethra acuminata is a native plant to the lower 48 states of the United States. It is an understory shrub found in the Appalachian region of the eastern United States. Other common names of Clethra acuminata include cinnamon clethra, mountain sweetpepperbush, and mountain sweet pepperbush. Clethra acuminata is a distinct species due to its floral and vegetative morphology within the genus. While Clethra acuminata is sometimes misidentified as Clethra alnifolia, they are two distinct species, Clethra acuminata has longer leaves.
Clethra acuminata can reach as high as 6 m (20 ft) tall. It has alternately arranged, acuminate leaves with fine teeth along the margins, 8–20 cm (3.1–7.9 in) long, glabrous above and slightly hairy or glabrous underneath. Clethra acuminata is a dicot perennial and a temperate deciduous shrub.
The leaves are simple and crowded towards the ends of branches, and the bisexual flowers are typically white and bell-shaped and less than one inch in length.
The flowers of Clethra acuminata grow in cone shaped racemes that vary from three to eight inches in length. The flowers are rich in nectar, which helps to support native pollinators. The flowers of C. acuminata bloom from the months of June to August. C. acuminata flowers are lost during winter and are replaced by brown capsule fruit. The seeds are typically eaten by birds and are displayed from September to October. The leaves of C. acuminata turn yellow and orange during the fall.
As C. acuminata ages, the bark peels to show a cinnamon colored interior; this is where one of its common names, cinnamon clethra, originates. Clethra acuminata can grow from eight to twenty feet in height and four to six feet in width. Bark on older plants splits and peels in thin sheets, revealing cinnamon colored bark underneath. Inflorescences are 3–8 inches (7.6–20.3 cm) racemes with bell-shaped white flowers.
Clethra acumniata is commonly mistaken for Clethra alnifolia due to their similar appearances, the differences are many, but the most recognizable difference lies in their leaf shape Clethra acuminata has 8–20 cm long leaves that do not have deep serrations while Clethra alnifolia has 7–10 cm long leaves with deep serrations along the upper half of the leaf’s edges. Clethra accuminata is also different from Clethra alnifolia at its pubescent stages and in the number of vascular suppliers to the sepals.
Clethra acuminata should be grown in moist soil, and has been recognized as an important pollinator plant, in native plant gardens, supporting and attracting hummingbirds, butterflies, and honeybees. Clethra acuminata is most successfully cultivated when grown in partial sun. If grown successfully, C. acuminata can grow to more than twenty feet tall. The best soil type for C. acuminata is moist, humus-rich, an acidic pH less than six is preferable, as well as a rockier soil type.
There are no common pest issues; however, root rot is common. There is no seed pretreatment required for seed germination. Clethra acuminata responds well to pruning and maintains its shape well. Clethra acuminata is a good choice for cultivation due to its heartiness against common pests -including deer-, disease, and physiological problems.
II. How to Grow and Care
Sunlight
This native plant will grow in full sun to total shade, but will grow best in light, dappled shade, or with morning sun and afternoon shade. These shrubs will even bloom profusely in complete shade.
Watering
Thriving in its native humid woodland settings, mountain sweet pepperbush has adapted to prefer consistent moisture, yet it can tolerate short dry spells. The plant’s watering regimen should mimic its natural environment, with a schedule of once every three weeks. Mountain sweet pepperbush is typically an outdoor plant that flourishes when the soil remains evenly damp but not waterlogged, highlighting the importance of well-draining soil to prevent root rot and maintain optimal hydration levels.
Soil
Cinnamon Clethra is a wonderful, trouble-free shrub with three seasons of interest, perfect for moist, slightly acidic, well-drained soils.
Fertilizing
For mountain sweet pepperbush, apply a balanced fertilizer (like 10-10-10) in spring to stimulate robust growth and flowering; a high nitrogen option may be used for boosting foliage. Fertilize once at the beginning of the growing season, and again mid-summer if necessary, adhering to package instructions for proper dosage. Over-fertilizing can harm mountain sweet pepperbush, so be cautious with quantity. During dormant winter months, refrain from fertilization. For effectiveness, water soil prior to applying fertilizer. This targeted feeding enhances mountain sweet pepperbush’s health and floriferous ness, crucial for plant vigor.
Propagation
Mountain sweet pepperbush is a deciduous shrub known for its fragrant, white flowers and versatility in landscaping. To propagate mountain sweet pepperbush, cuttings offer a reliable method. Select healthy semi-hardwood stems and trim them to include several leaf nodes. Provide a well-draining soil mix and maintain consistent moisture without overwatering. Rooting hormone can enhance success rates, while gentle bottom heat promotes root development. After rooting, gradually acclimate the young mountain sweet pepperbush to outdoor conditions before transplanting them into their permanent location.
Pests and Diseases
This plant enjoys excellent resistance to pests and diseases. However, keep an eye out for fungal dieback and root rot. Deer resistant.
III. Uses and BenefitsÂ
Mountain sweet pepperbush is excellent as a specimen plant, in small groupings, shrub borders, or the woodland understory.
