Watermelon Berry Plant Care

Watermelon Berry (Syzygium tierneyanum) belongs to the Myrtaceae family within the Syzygium genus. Watermelon Berry is native to New Guinea, the Solomon Islands, Vanuatu and north east Queensland.

Watermelon Berry displays a tall, dense tree or shrub growth habit, reaching up to 20 ft tall with a spread of approximately 15 ft. Watermelon Berry produces small, white, fluffy flowers in clusters.

Leaf size: approximately 4 inches.

Water a young or newly planted Watermelon Berry 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.

Watermelon Berry thrives in full sun to partial shade.

Syzygium tierneyanum tolerates temperatures of 60–85°F. Watermelon Berry prefers humidity levels of 50–80%. A pebble tray or humidifier helps maintain adequate moisture around the plant.

Well-draining, slightly acidic soil with added organic matter like compost or peat moss. Good drainage is essential for Watermelon Berry to prevent waterlogging, which leads to root rot and fungal issues.

Feed Watermelon Berry 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 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.

Watermelon Berry is suited to USDA Zone 10b – 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.

Watermelon Berry 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.

Prune Watermelon Berry 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.

Watermelon Berry is frost-tender (hardy to USDA zone 10). In colder areas grow it in a container and move it to a bright, frost-free place before the first frost.

Watermelon Berry can be propagated through seeds, semi-hardwood cuttings. Similar propagation techniques also apply to waterberry plant care, which shares the same genus.

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

Watermelon Berry 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.

Watermelon Berry grows outdoors in USDA Zone 10b – 12b. It survives winters down to planting zone 10b. Watermelon Berry is native to New Guinea, the Solomon Islands, Vanuatu and north east Queensland. In cooler regions, grow Watermelon Berry as a houseplant or bring it indoors before the first frost.