Black Calabash Plant Care

Black Calabash (Hieronyma crassistipula) belongs to the Phyllanthaceae family within the Hieronyma genus. Black Calabash is native to Cuba's Isla de la Juventud. Black Calabash is also known as Soapberry Tree, Wild Cinnamon.

Black Calabash displays a tall tree, spreading canopy growth habit, reaching up to 30 ft tall with a spread of approximately 20 ft. Black Calabash produces small greenish-yellow flowers in clusters.

Leaf size: approximately 6 inches.

Water a young or newly planted Black Calabash every 7–14 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.

Black Calabash thrives in partial to full sun.

Hieronyma crassistipula tolerates temperatures of 65–85°F. Black Calabash prefers humidity levels of 50–80%. A pebble tray or humidifier helps maintain adequate moisture around the plant.

Well-draining loamy soil mix with added organic matter for moisture retention. Good drainage is essential for Black Calabash to prevent waterlogging, which leads to root rot and fungal issues.

Feed Black Calabash 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 to full sun and well-draining loamy soil mix with added organic matter for moisture retention. Avoid low spots where water collects after rain.

Black Calabash is suited to USDA Zone 13b – 12b.

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.

Black Calabash can spread to about 20 ft (6.1 m) and reach about 30 ft (9 m) tall. Space plants about 20 ft (6.1 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 Black Calabash 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.

Black Calabash is frost-tender (hardy to USDA zone 13). In colder areas grow it in a container and move it to a bright, frost-free place before the first frost.

Black Calabash can be propagated through seeds, stem cuttings. Similar propagation techniques also apply to clusius hieronyma plant care, which shares the same genus.

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

Black Calabash is susceptible to mealybugs, spider mites, scale insects. 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.

Black Calabash grows outdoors in USDA Zone 13b – 12b. It survives winters down to planting zone 13b. Black Calabash is native to Cuba's Isla de la Juventud. In cooler regions, grow Black Calabash as a houseplant or bring it indoors before the first frost.