Sepik horsfieldia Plant Care

Sepik horsfieldia (Horsfieldia sepikensis) belongs to the Myristicaceae family within the Horsfieldia genus. Sepik horsfieldia is native to Papua New Guinea. Sepik horsfieldia is also known as Sepik river walnut.

Sepik horsfieldia displays a tall, upright tree growth habit, reaching up to 30 ft tall with a spread of approximately 15 ft. Sepik horsfieldia produces small, inconspicuous flowers.

Leaf size: approximately 6 inches.

Water a young or newly planted Sepik horsfieldia 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.

Sepik horsfieldia thrives in filtered sunlight. Avoid placing Sepik horsfieldia in direct, harsh sunlight for extended periods, as this can scorch the foliage.

Horsfieldia sepikensis tolerates temperatures of 65–80°F. Sepik horsfieldia prefers humidity levels of 60–80%. A pebble tray or humidifier helps maintain adequate moisture around the plant.

Rich, well-draining soil with high organic content. Good drainage is essential for Sepik horsfieldia to prevent waterlogging, which leads to root rot and fungal issues.

Feed Sepik horsfieldia 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 filtered sunlight and rich, well-draining soil with high organic content. Avoid low spots where water collects after rain.

Sepik horsfieldia 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.

Sepik horsfieldia can spread to about 15 ft (4.6 m) and reach about 30 ft (9 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 Sepik horsfieldia 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.

Sepik horsfieldia 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.

Sepik horsfieldia can be propagated through seeds, air layering. Similar propagation techniques also apply to red bloodwood plant care, which shares the same genus.

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Sepik horsfieldia is susceptible to spider mites, 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.

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