Rough Mentzelia Plant Care

Rough Mentzelia (Mentzelia aspera) belongs to the Loasaceae family within the Mentzelia genus. Rough Mentzelia is native to the subtropical and tropical New World, from Arizona to northwestern Argentina, and it has been introduced to Cape Verde.

Rough Mentzelia displays an upright, branching growth habit, reaching up to 2 ft tall with a spread of approximately 1.5 ft. Rough Mentzelia produces bright yellow, cup-shaped flowers.

Leaf size: approximately 3 inches.

Water a young or newly planted Rough Mentzelia 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.

Rough Mentzelia thrives in full sun to partial shade.

Mentzelia aspera tolerates temperatures of 50–85°F. Rough Mentzelia prefers humidity levels of 30–60%.

Well-draining sandy soil with some organic matter. Good drainage is essential for Rough Mentzelia to prevent waterlogging, which leads to root rot and fungal issues.

Feed Rough Mentzelia 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 some organic matter. Avoid low spots where water collects after rain.

Rough Mentzelia is suited to USDA Zone 12a.

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.

Rough Mentzelia can spread to about 2 ft (0.5 m) and reach about 2 ft (1 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 Rough Mentzelia 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.

Rough Mentzelia is frost-tender (hardy to USDA zone 12). In colder areas grow it in a container and move it to a bright, frost-free place before the first frost.

Rough Mentzelia can be propagated through seeds. Similar propagation techniques also apply to showy stickleaf plant care, which shares the same genus.

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

Rough Mentzelia 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.

Rough Mentzelia grows outdoors in USDA Zone 12a. It survives winters down to planting zone 12a. Rough Mentzelia is native to the subtropical and tropical New World, from Arizona to northwestern Argentina, and it has been introduced to Cape Verde. In cooler regions, grow Rough Mentzelia as a houseplant or bring it indoors before the first frost.