Slender Arnica Plant Care

Slender Arnica (Arnica gracilis) belongs to the Asteraceae family within the Arnica genus. Slender Arnica is native to western Canada and the northwestern United States (Washington, Oregon, Idaho, Montana, Wyoming, north-central Colorado, and northern Utah.

Slender Arnica displays a low rosette, clumping growth habit, reaching up to 1.5 ft tall with a spread of approximately 1 ft. Slender Arnica produces bright yellow daisy-like flowers.

Leaf size: approximately 4 inches.

Water a young or newly planted Slender Arnica 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.

Slender Arnica thrives in full sun to partial shade.

Arnica gracilis tolerates temperatures of 60–75°F. Slender Arnica prefers humidity levels of 40–60%.

Well-draining, loamy soil with good organic content. Good drainage is essential for Slender Arnica to prevent waterlogging, which leads to root rot and fungal issues.

Feed Slender Arnica 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, loamy soil with good organic content. Avoid low spots where water collects after rain.

Slender Arnica 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.

Slender Arnica can spread to about 1 ft (0.3 m) and reach about 2 ft (0 m) tall. Space plants about 1 ft (0.3 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 Slender Arnica 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.

Slender Arnica 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.

Slender Arnica can be propagated through seeds, division of rhizomes. Similar propagation techniques also apply to doronicum acaule plant care, which shares the same genus.

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

Slender Arnica is susceptible to aphids, whiteflies, spider mites. 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.

Slender Arnica grows outdoors in USDA Zone 13a. It survives winters down to planting zone 13a. Slender Arnica is native to western Canada and the northwestern United States (Washington, Oregon, Idaho, Montana, Wyoming, north-central Colorado, and northern Utah. In cooler regions, grow Slender Arnica as a houseplant or bring it indoors before the first frost.