Waterhousea Plant Care
Syzygium moorei (F.Muell.) L.A.S.Johnson
Updated · Sources · How we source care data
Syzygium moorei is a rare sub tropical rainforest tree, growing on volcanic soils in the Mount Warning area of north east New South Wales and south east Queensland, Australia. Common names include coolamon, watermelon tree, durobby and robby; it is also called "rose apple" but this can refer to many species of Syzygium.
Every 7–14 days
Full sun to partial shade
60–85°F
50–80%
At a glance
How do you care for Waterhousea?
Plant Waterhousea in full sun to partial shade (USDA zones 13a) and water a young tree every 7–14 days until it is established. It tolerates temperatures of 60–85°F (16–29°C). Fertilize it every 6 months during the growing season.
What Is the Waterhousea?
Waterhousea (Syzygium moorei) belongs to the Myrtaceae family within the Syzygium genus. Waterhousea is also known as Rose Apple.
Waterhousea displays a tall, dense tree or shrub growth habit, reaching up to 20 ft tall with a spread of approximately 15 ft. Waterhousea produces small, white, fluffy flowers in clusters.
Leaf size: approximately 4 inches.
How Often Should You Water a Waterhousea?
Water a young or newly planted Waterhousea 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 Waterhousea Need?
Waterhousea thrives in full sun to partial shade.
Light Requirement
Full sun to partial shade
What Temperature and Humidity Does the Waterhousea Prefer?
Syzygium moorei tolerates temperatures of 60–85°F. Waterhousea prefers humidity levels of 50–80%. A pebble tray or humidifier helps maintain adequate moisture around the plant.
Temperature
60–85°F
Humidity
50–80%
What Soil Mix Works Best for a Waterhousea?
Well-draining, slightly acidic soil with added organic matter like compost or peat moss. Good drainage is essential for Waterhousea to prevent waterlogging, which leads to root rot and fungal issues.
How Often Should You Fertilize a Waterhousea?
Feed Waterhousea 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.
Fertilizing
Every 6 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 Waterhousea?
Choose a spot with full sun to partial shade and well-draining, slightly acidic soil with added organic matter like compost or peat moss. Avoid low spots where water collects after rain.
Waterhousea is suited to USDA Zone 13a.
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 Waterhousea?
Waterhousea can spread to about 15 ft (4.6 m) and reach about 20 ft (6 m) tall. Space plants about 15 ft (4.6 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 Waterhousea?
Prune Waterhousea 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 Waterhousea in Winter?
Waterhousea 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 Waterhousea?
Waterhousea can be propagated through seeds, semi-hardwood cuttings. Similar propagation techniques also apply to waterberry plant care, which shares the same genus.
Is the Waterhousea Toxic to Pets and Children?
Pet safety not verified
The ASPCA does not list Waterhousea, 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 Waterhousea?
Waterhousea is susceptible to aphids, 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.
What USDA Hardiness Zone Does the Waterhousea Need?
Waterhousea grows outdoors in USDA Zone 13a. It survives winters down to planting zone 13a. In cooler regions, grow Waterhousea as a houseplant or bring it indoors before the first frost.
Hardiness Zone
Zone 13a
Keep exploring plants
Waterhousea 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 Syzygium genus — compare its care with other Syzygium species on PlantoScan.
Syzygium is part of the Myrtaceae plant family — browse all Myrtaceae genera and species.
Waterhousea thrives in bright light and direct sun — see other bright-light plants.
More Syzygium Species
Other Syzygium species in PlantoScan's care catalogue share similar watering, light, and soil preferences:
Sources
- Scientific name & taxonomy: Syzygium moorei (F.Muell.) L.A.S.Johnson, family Myrtaceae (first published in Contr. New South Wales Natl. Herb. 3: 99 (1962)) — World Flora Online record, IPNI name record.
- Pet toxicity: Pet safety not verified: the ASPCA does not list Waterhousea, 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 13a, 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.
