Smallflower Sumpweed Plant Care

Smallflower Sumpweed (Iva microcephala) belongs to the Asteraceae family within the Iva genus.

Smallflower Sumpweed displays an upright, branching shrub growth habit, reaching up to 3 ft tall with a spread of approximately 2 ft. Smallflower Sumpweed produces small, inconspicuous greenish-white flowers in clusters.

Leaf size: approximately 4 inches.

Water a young or newly planted Smallflower Sumpweed 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.

Smallflower Sumpweed thrives in full sun to partial shade.

Iva microcephala tolerates temperatures of 65–85°F. Smallflower Sumpweed prefers humidity levels of 40–60%.

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

Feed Smallflower Sumpweed 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 loam with added organic matter. Avoid low spots where water collects after rain.

Smallflower Sumpweed 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.

Smallflower Sumpweed 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 Smallflower Sumpweed 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.

Smallflower Sumpweed 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.

Smallflower Sumpweed can be propagated through seeds, division of root ball. Similar propagation techniques also apply to annual sumpweed plant care, which shares the same genus.

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Smallflower Sumpweed 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.

Smallflower Sumpweed grows outdoors in USDA Zone 13b. It survives winters down to planting zone 13b. In cooler regions, grow Smallflower Sumpweed as a houseplant or bring it indoors before the first frost.