Japanese mugwort Plant Care

Japanese mugwort (Artemisia japonica) belongs to the Asteraceae family within the Artemisia genus. Japanese mugwort is native to Japan, Korea, China, Southeast Asia, and the Indian Subcontinent. Japanese mugwort is also known as Japanese wormwood, Artemisia japonica.

Japanese mugwort displays an upright, bushy shrub growth habit, reaching up to 2 ft tall with a spread of approximately 3 ft. Japanese mugwort produces insignificant small yellow or white flowers.

Leaf size: approximately 2 inches.

Water a young or newly planted Japanese mugwort every 7–14 days, soaking the whole root zone, until it is established — usually one to two growing seasons. Established shrubs mainly need water during long dry spells. In a container, water whenever the top few centimetres of soil are dry.

Japanese mugwort thrives in full sun to partial shade.

Artemisia japonica tolerates temperatures of 50–75°F. Japanese mugwort prefers humidity levels of 30–60%.

Well-draining sandy soil with low fertility. Good drainage is essential for Japanese mugwort to prevent waterlogging, which leads to root rot and fungal issues.

Feed Japanese mugwort every 6 months during the growing season with a balanced, slow-release fertilizer at the rate on the label. Established shrubs 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 sandy soil with low fertility. Avoid low spots where water collects after rain.

Japanese mugwort is suited to USDA Zone 5a – 9b.

Plant container-grown or balled-and-burlapped shrubs in spring or early autumn, setting the root flare at soil level, and water well after planting.

Japanese mugwort can spread to about 3 ft (0.9 m) and reach about 2 ft (1 m) tall. Space plants about 3 ft (0.9 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 plant spacing calculator.

Prune Japanese mugwort 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 shrub in one year.

Japanese mugwort is hardy down to USDA zone 5a, 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 shrubs need extra protection: roots in a pot freeze much more easily than roots in the ground.

Japanese mugwort can be propagated through seeds, division. Similar propagation techniques also apply to southernwood plant care, which shares the same genus.

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Japanese mugwort is susceptible to aphids, spider mites. 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 mugwort grows outdoors in USDA Zone 5a – 9b. It survives winters down to planting zone 5a. Japanese mugwort is native to Japan, Korea, China, Southeast Asia, and the Indian Subcontinent.