Mountain Pepperbush Plant Care

Mountain Pepperbush (Clethra acuminata) belongs to the Clethraceae family within the Clethra genus. Mountain Pepperbush is native to the Appalachian Mountains of the southeastern United States. Mountain Pepperbush is also known as Cinnamon Clethra.

Mountain Pepperbush displays an upright, spreading shrub growth habit, reaching up to 6 ft tall with a spread of approximately 8 ft. Mountain Pepperbush produces fragrant white or pink bottlebrush-like flowers.

Leaf size: approximately 4 inches.

Water a young or newly planted Mountain Pepperbush every 3–7 days, soaking the whole root zone, until it is established — usually one to two growing seasons. Established trees mainly need water during long dry spells. In a container, water whenever the top few centimetres of soil are dry.

Mountain Pepperbush thrives in partial shade to full sun.

Clethra acuminata tolerates temperatures of 50–80°F. Mountain Pepperbush prefers humidity levels of 40–70%.

Moist, acidic, well-draining soil rich in organic matter. Good drainage is essential for Mountain Pepperbush to prevent waterlogging, which leads to root rot and fungal issues.

Feed Mountain Pepperbush every 6 months during the growing season with a balanced, slow-release fertilizer at the rate on the label. Established trees in good soil often need little extra feeding, so let weak growth or pale foliage guide you.

Stop feeding by late summer so new growth can harden before winter.

The PlantoScan app can remind you when to water and when to fertilize each plant.

Choose a spot with partial shade to full sun and moist, acidic, well-draining soil rich in organic matter. Avoid low spots where water collects after rain.

Mountain Pepperbush is suited to USDA Zone 12a.

Plant container-grown or balled-and-burlapped trees in spring or early autumn, setting the root flare at soil level, and water well after planting.

Mountain Pepperbush can spread to about 8 ft (2.4 m) and reach about 6 ft (2 m) tall. Space plants about 8 ft (2.4 m) apart so mature crowns don't crowd each other, and plant at least half that distance from buildings, fences and paths.

Planning a row or hedge? Try the tree spacing calculator.

Prune Mountain Pepperbush while it is dormant in late winter: first remove dead, damaged and crossing branches, then thin lightly for shape.

If it flowers in spring, prune right after flowering instead so you don't remove next year's buds. Never take off more than about a quarter of the tree in one year.

Mountain Pepperbush is frost-tender (hardy to USDA zone 12). In colder areas grow it in a container and move it to a bright, frost-free place before the first frost.

Mountain Pepperbush can be propagated through softwood cuttings, seeds. Similar propagation techniques also apply to sweet pepperbush plant care, which shares the same genus.

See all plants toxic to cats and plants toxic to dogs.

Mountain Pepperbush is susceptible to aphids, scale insects, spider mites. Inspect the foliage regularly, especially along leaf undersides and stems. Treat infestations promptly with insecticidal soap or neem oil to prevent spread.

Yellow leaves, brown tips or drooping? See common plant problems and how to fix them.

Mountain Pepperbush grows outdoors in USDA Zone 12a. It survives winters down to planting zone 12a. Mountain Pepperbush is native to the Appalachian Mountains of the southeastern United States. In cooler regions, grow Mountain Pepperbush as a houseplant or bring it indoors before the first frost.