Common Ragweed Plant Care

Common Ragweed (Ambrosia artemisiifolia) belongs to the Asteraceae family within the Ambrosia genus. Common Ragweed is native to regions of the Americas. Common Ragweed is also known as Annual Ragweed, Iva monophylla.

Common Ragweed displays a spreading, upright growth habit, reaching up to 6 ft tall with a spread of approximately 3 ft. Common Ragweed produces green, small, spike inflorescence.

Leaf size: approximately 2 inches.

Water a young or newly planted Common Ragweed every 5–7 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.

Common Ragweed thrives in full sun.

Ambrosia artemisiifolia tolerates temperatures of 65–85°F. Common Ragweed prefers humidity levels of 40–60%.

Well-drained, loamy soil. Good drainage is essential for Common Ragweed to prevent waterlogging, which leads to root rot and fungal issues.

Feed Common Ragweed every 5 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-drained, loamy soil. Avoid low spots where water collects after rain.

Common Ragweed is suited to USDA Zone 3a – 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.

Common Ragweed can spread to about 3 ft (0.9 m) and reach about 6 ft (2 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 tree spacing calculator.

Prune Common Ragweed 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.

Common Ragweed is hardy down to USDA zone 3a, 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.

Common Ragweed can be propagated through by seeds or division of rhizomes. Similar propagation techniques also apply to spiny bur ragweed plant care, which shares the same genus.

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Common Ragweed 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.

Common Ragweed grows outdoors in USDA Zone 3a – 13b. It survives winters down to planting zone 3a. Common Ragweed is native to regions of the Americas.