Siam Pentacme Plant Care

Siam Pentacme (Pentacme siamensis) belongs to the Dipterocarpaceae family within the Pentacme genus. Siam Pentacme is native to most of mainland Southeast Asia.

Siam Pentacme displays a tall canopy tree growth habit, reaching up to 100 ft tall with a spread of approximately 50 ft. Siam Pentacme produces small, inconspicuous flowers.

Leaf size: approximately 6 inches.

Water a young or newly planted Siam Pentacme 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 Pentacme thrives in full sun to partial shade.

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

Well-draining, loamy soil with high organic content. Good drainage is essential for Siam Pentacme to prevent waterlogging, which leads to root rot and fungal issues.

Feed Siam Pentacme every 8 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 full sun to partial shade and well-draining, loamy soil with high organic content. Avoid low spots where water collects after rain.

Siam Pentacme 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 Pentacme can spread to about 50 ft (15.2 m) and reach about 100 ft (30 m) tall. Space plants about 50 ft (15.2 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 Pentacme 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 Pentacme 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 Pentacme can be propagated through seeds, stem cuttings.

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

Siam Pentacme is susceptible to scale insects, caterpillars. 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 Pentacme grows outdoors in USDA Zone 13b. It survives winters down to planting zone 13b. Siam Pentacme is native to most of mainland Southeast Asia. In cooler regions, grow Siam Pentacme as a houseplant or bring it indoors before the first frost.