Karri She-oak Plant Care

Karri She-oak (Allocasuarina decussata) belongs to the Casuarinaceae family within the Allocasuarina genus. Karri She-oak is native to the southwest of Western Australia. Karri She-oak is also known as Black She-oak.

Karri She-oak displays a tall, slender tree growth habit, reaching up to 30 ft tall with a spread of approximately 15 ft. Karri She-oak produces small, inconspicuous flowers.

Leaf size: approximately 4 inches.

Water a young or newly planted Karri She-oak 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.

Karri She-oak thrives in full sun.

Allocasuarina decussata tolerates temperatures of 50–90°F. Karri She-oak prefers humidity levels of 40–70%.

Well-draining sandy soil mix with good aeration. Good drainage is essential for Karri She-oak to prevent waterlogging, which leads to root rot and fungal issues.

Feed Karri She-oak 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.

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

Choose a spot with full sun and well-draining sandy soil mix with good aeration. Avoid low spots where water collects after rain.

Karri She-oak is suited to USDA Zone 9a – 11a.

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.

Karri She-oak 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 Karri She-oak 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.

Karri She-oak is frost-tender (hardy to USDA zone 9). In colder areas grow it in a container and move it to a bright, frost-free place before the first frost.

Karri She-oak can be propagated through seeds, cuttings. Similar propagation techniques also apply to sharp-leaved sheoak plant care, which shares the same genus.

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

Karri She-oak is susceptible to aphids, 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.

Karri She-oak grows outdoors in USDA Zone 9a – 11a. It survives winters down to planting zone 9a. Karri She-oak is native to the southwest of Western Australia. In cooler regions, grow Karri She-oak as a houseplant or bring it indoors before the first frost.