Siam Mammee Apple Plant Care

Siam Mammee Apple (Mammea siamensis) belongs to the Calophyllaceae family within the Mammea genus.

Siam Mammee Apple displays a large canopy tree growth habit, reaching up to 50 ft tall with a spread of approximately 30 ft. Siam Mammee Apple produces large, fragrant white flowers with waxy petals.

Leaf size: approximately 8 inches.

Water a young or newly planted Siam Mammee Apple 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.

Siam Mammee Apple thrives in partial shade to full sun.

Mammea siamensis tolerates temperatures of 65–85°F. Siam Mammee Apple prefers humidity levels of 60–80%. A pebble tray or humidifier helps maintain adequate moisture around the plant.

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

Feed Siam Mammee Apple 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 well-draining, rich loamy soil with added organic matter for moisture retention. Avoid low spots where water collects after rain.

Siam Mammee Apple is suited to USDA Zone 13b.

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.

Siam Mammee Apple can spread to about 30 ft (9.1 m) and reach about 50 ft (15 m) tall. Space plants about 30 ft (9.1 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 Siam Mammee Apple 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.

Siam Mammee Apple 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.

Siam Mammee Apple can be propagated through seeds, air layering. Similar propagation techniques also apply to mammee apple plant care, which shares the same genus.

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Siam Mammee Apple is susceptible to scale insects, mealybugs, 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.

Siam Mammee Apple grows outdoors in USDA Zone 13b. It survives winters down to planting zone 13b. In cooler regions, grow Siam Mammee Apple as a houseplant or bring it indoors before the first frost.