Arrowleaf Thoroughwort Plant Care

Arrowleaf Thoroughwort (Chromolaena sagittata) belongs to the Asteraceae family within the Chromolaena genus. Arrowleaf Thoroughwort is native to western Mexico, in the states of Sonora, Sinaloa, Nayarit, and Baja California Sur.

Arrowleaf Thoroughwort displays an upright, spreading shrub growth habit, reaching up to 3 ft tall with a spread of approximately 2 ft. Arrowleaf Thoroughwort produces small white or lavender flowers in clusters.

Leaf size: approximately 6 inches.

Water a young or newly planted Arrowleaf Thoroughwort every 7–10 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.

Arrowleaf Thoroughwort thrives in full sun to partial shade.

Chromolaena sagittata tolerates temperatures of 65–85°F. Arrowleaf Thoroughwort prefers humidity levels of 40–70%.

Well-draining sandy loam with added organic matter. Good drainage is essential for Arrowleaf Thoroughwort to prevent waterlogging, which leads to root rot and fungal issues.

Feed Arrowleaf Thoroughwort every 4 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 loam with added organic matter. Avoid low spots where water collects after rain.

Arrowleaf Thoroughwort is suited to USDA Zone 13b.

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.

Arrowleaf Thoroughwort can spread to about 2 ft (0.6 m) and reach about 3 ft (1 m) tall. Space plants about 2 ft (0.6 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 plant spacing calculator.

Prune Arrowleaf Thoroughwort 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.

Arrowleaf Thoroughwort 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.

Arrowleaf Thoroughwort can be propagated through seeds, stem cuttings. Similar propagation techniques also apply to bigelow's thoroughwort plant care, which shares the same genus.

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Arrowleaf Thoroughwort is susceptible to aphids, spider mites, whiteflies. 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.

Arrowleaf Thoroughwort grows outdoors in USDA Zone 13b. It survives winters down to planting zone 13b. Arrowleaf Thoroughwort is native to western Mexico, in the states of Sonora, Sinaloa, Nayarit, and Baja California Sur. In cooler regions, grow Arrowleaf Thoroughwort as a houseplant or bring it indoors before the first frost.