Japanese sassafras Plant Care

Japanese sassafras (Sassafras thunbergii) belongs to the Lauraceae family within the Sassafras genus. Japanese sassafras is native to Japan. Japanese sassafras is also known as Thunberg's sassafras.

Japanese sassafras displays a medium-sized deciduous tree growth habit, reaching up to 30 ft tall with a spread of approximately 25 ft. Japanese sassafras produces small yellow-green flowers in clusters.

Leaf size: approximately 6 inches.

Water a young or newly planted Japanese sassafras 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.

Japanese sassafras thrives in full sun to partial shade.

Sassafras thunbergii tolerates temperatures of 20–100°F. Japanese sassafras prefers humidity levels of 40–70%.

Moist, well-draining loamy soil with added organic matter. Good drainage is essential for Japanese sassafras to prevent waterlogging, which leads to root rot and fungal issues.

Feed Japanese sassafras 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 moist, well-draining loamy soil with added organic matter. Avoid low spots where water collects after rain.

Japanese sassafras is suited to USDA Zone 6a – 9b.

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.

Japanese sassafras can spread to about 25 ft (7.6 m) and reach about 30 ft (9 m) tall. Space plants about 25 ft (7.6 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 Japanese sassafras 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.

Japanese sassafras is hardy down to USDA zone 6a, so once established it can stay outdoors through winter in that zone and warmer ones.

Water deeply in late autumn before the ground freezes, and spread a 5–8 cm (2–3 in) layer of mulch over the root zone, keeping it away from the trunk.

Young and container-grown trees need extra protection: roots in a pot freeze much more easily than roots in the ground.

Japanese sassafras can be propagated through seeds, root cuttings. Similar propagation techniques also apply to sassafras plant care, which shares the same genus.

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Japanese sassafras is susceptible to powdery mildew, scale insects, borers. 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.

Japanese sassafras grows outdoors in USDA Zone 6a – 9b. It survives winters down to planting zone 6a. Japanese sassafras is native to Japan.