Mersawa Plant Care

Shorea obtusa Wall. ex Blume

Updated · Sources · How we source care data

Shorea obtusa, the Siamese sal, is a species of hardwood tree in the family Dipterocarpaceae, native to Southeast Asia.

Water

Every 7–14 days

Light

Full sun

Temp

65–85°F

Humidity

60–80%

At a glance

How do you care for Mersawa?

Plant Mersawa in full sun (USDA zones 13b) and water a young tree every 7–14 days until it is established. It tolerates temperatures of 65–85°F (18–29°C). Fertilize it every 8 months during the growing season.

Where Is the Mersawa Native To?

Native range11 countries

What Is the Mersawa?

Mersawa (Shorea obtusa) belongs to the Dipterocarpaceae family within the Shorea genus. Mersawa is native to Southeast Asia. Mersawa is also known as Terkilan.

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

Leaf size: approximately 6 inches.

How Often Should You Water a Mersawa?

Water a young or newly planted Mersawa 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.

Watering Frequency

Every 7–14 days

Until established; then in dry spells

What Light Does the Mersawa Need?

Mersawa thrives in full sun.

Light Requirement

Full sun

What Temperature and Humidity Does the Mersawa Prefer?

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

Temperature

65–85°F

Humidity

60–80%

What Soil Mix Works Best for a Mersawa?

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

How Often Should You Fertilize a Mersawa?

Feed Mersawa 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.

Fertilizing

Every 8 months

During the growing season

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

Where Should You Plant a Mersawa?

Choose a spot with full sun and well-draining loamy soil with high organic content. Avoid low spots where water collects after rain.

Mersawa 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.

How Far Apart Should You Plant a Mersawa?

Mersawa 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.

How Do You Prune a Mersawa?

Prune Mersawa 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.

How Do You Care for a Mersawa in Winter?

Mersawa 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.

How Do You Propagate a Mersawa?

Mersawa can be propagated through seeds, cuttings. Similar propagation techniques also apply to meranti plant care, which shares the same genus.

Is the Mersawa Toxic to Pets and Children?

Pet safety not verified

The ASPCA does not list Mersawa, so we can't confirm whether it is safe for cats and dogs. Keep pets from chewing it as a precaution.

This is a general caution, not veterinary or medical advice. If your pet ate a plant, contact your vet or animal poison control.

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

What Pests and Diseases Affect the Mersawa?

Mersawa is susceptible to termites, 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.

What USDA Hardiness Zone Does the Mersawa Need?

Mersawa grows outdoors in USDA Zone 13b. It survives winters down to planting zone 13b. Mersawa is native to Southeast Asia. In cooler regions, grow Mersawa as a houseplant or bring it indoors before the first frost.

Hardiness Zone

Zone 13b

Keep exploring plants

Mersawa is one of many species covered in the complete plant care and identification guide, which groups plants by genus, attribute, and popularity.

It belongs to the Shorea genus — compare its care with other Shorea species on PlantoScan.

Shorea is part of the Dipterocarpaceae plant family — browse all Dipterocarpaceae genera and species.

Mersawa thrives in bright light and direct sun — see other bright-light plants.

More Shorea Species

Other Shorea species in PlantoScan's care catalogue share similar watering, light, and soil preferences:

Sources

  • Scientific name & taxonomy: Shorea obtusa Wall. ex Blume, family Dipterocarpaceae (first published in Mus. Bot. 2: 32 (1856)) — World Flora Online record, IPNI name record.
  • Pet toxicity: Pet safety not verified: the ASPCA does not list Mersawa, so we can't confirm whether it is safe for cats and dogs. Checked against the ASPCA plant list; any other toxicity note on this page comes from PlantoScan's plant database.
  • Hardiness zone: USDA Zone 13b, calculated from the plant's minimum temperature.
  • Care values(watering, light, temperature, humidity, soil, fertilizing): PlantoScan's plant database, filtered by automatic plausibility checks — values that fail them are hidden. How we source and check plant data.

Spotted a mistake? Email info@upvision.media with the page link — we check and correct reported errors.

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