Giant Tree Aralia Plant Care

Giant Tree Aralia (Harmsiopanax ingens) belongs to the Araliaceae family within the Harmsiopanax genus. Giant Tree Aralia is native to the montane rainforests of central New Guinea which bears a terminal rosette of deeply lobed, dentate margined, usually peltate leaves 1 m across, maple-like in shape, on equally long petioles.

Giant Tree Aralia displays a tall, upright tree growth habit, reaching up to 15 ft tall with a spread of approximately 8 ft. Giant Tree Aralia produces small white flowers in umbels.

Leaf size: approximately 12 inches.

Water a young or newly planted Giant Tree Aralia 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.

Giant Tree Aralia thrives in bright indirect light. Avoid placing Giant Tree Aralia in direct, harsh sunlight for extended periods, as this can scorch the foliage.

Harmsiopanax ingens tolerates temperatures of 65–80°F. Giant Tree Aralia prefers humidity levels of 50–70%. A pebble tray or humidifier helps maintain adequate moisture around the plant.

Rich, well-draining soil with added organic matter like compost or peat moss. Good drainage is essential for Giant Tree Aralia to prevent waterlogging, which leads to root rot and fungal issues.

Feed Giant Tree Aralia 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 bright indirect light and rich, well-draining soil with added organic matter like compost or peat moss. Avoid low spots where water collects after rain.

Giant Tree Aralia 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.

Giant Tree Aralia can spread to about 8 ft (2.4 m) and reach about 15 ft (5 m) tall. Space plants about 8 ft (2.4 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 Giant Tree Aralia 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.

Giant Tree Aralia 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.

Giant Tree Aralia can be propagated through seeds, stem cuttings.

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

Giant Tree Aralia is susceptible to spider mites, scale insects, aphids. 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.

Giant Tree Aralia grows outdoors in USDA Zone 13b. It survives winters down to planting zone 13b. Giant Tree Aralia is native to the montane rainforests of central New Guinea which bears a terminal rosette of deeply lobed, dentate margined, usually peltate leaves 1 m across, maple-like in shape, on equally long petioles. In cooler regions, grow Giant Tree Aralia as a houseplant or bring it indoors before the first frost.