Grayleaf Parthenium Plant Care

Grayleaf Parthenium (Parthenium incanum) belongs to the Asteraceae family within the Parthenium genus. Grayleaf Parthenium is also known as Mariola, Parthenium ramosissimum.

Grayleaf Parthenium displays a low rosette, spreading ground cover growth habit, reaching up to 0.5 ft tall with a spread of approximately 1.5 ft. Grayleaf Parthenium produces small white daisy-like flowers in clusters.

Leaf size: approximately 2 inches.

Water a young or newly planted Grayleaf Parthenium 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.

Grayleaf Parthenium thrives in full sun to partial shade.

Parthenium incanum tolerates temperatures of 60–80°F. Grayleaf Parthenium prefers humidity levels of 40–70%.

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

Feed Grayleaf Parthenium 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.

Grayleaf Parthenium is suited to USDA Zone 13a.

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.

Grayleaf Parthenium can spread to about 2 ft (0.5 m) and reach about 1 ft (0 m) tall. Space plants about 2 ft (0.5 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 Grayleaf Parthenium 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.

Grayleaf Parthenium 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.

Grayleaf Parthenium can be propagated through seeds, division of clumps. Similar propagation techniques also apply to parthenium weed plant care, which shares the same genus.

See all plants toxic to cats and plants toxic to dogs.

Grayleaf Parthenium 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.

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