Howell's gumweed Plant Care

Howell's gumweed (Grindelia howellii) belongs to the Asteraceae family within the Grindelia genus. Howell's gumweed is native to the northwestern United States, in the States of Idaho and Montana.

Howell's gumweed displays an upright, branching shrub growth habit, reaching up to 3 ft tall with a spread of approximately 2 ft. Howell's gumweed produces bright yellow daisy-like flowers.

Leaf size: approximately 4 inches.

Water a young or newly planted Howell's gumweed 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.

Howell's gumweed thrives in full sun to partial shade.

Grindelia howellii tolerates temperatures of 50–85°F. Howell's gumweed prefers humidity levels of 40–70%.

Well-draining sandy soil mix with some organic matter. Good drainage is essential for Howell's gumweed to prevent waterlogging, which leads to root rot and fungal issues.

Feed Howell's gumweed 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 mix with some organic matter. Avoid low spots where water collects after rain.

Howell's gumweed 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.

Howell's gumweed 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 Howell's gumweed 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.

Howell's gumweed 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.

Howell's gumweed can be propagated through seeds, division of roots. Similar propagation techniques also apply to ciliate gumweed plant care, which shares the same genus.

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Howell's gumweed is susceptible to aphids, caterpillars, 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.

Howell's gumweed grows outdoors in USDA Zone 12a. It survives winters down to planting zone 12a. Howell's gumweed is native to the northwestern United States, in the States of Idaho and Montana. In cooler regions, grow Howell's gumweed as a houseplant or bring it indoors before the first frost.