Blackbrush Plant Care

Blackbrush (Flourensia cernua) belongs to the Asteraceae family within the Flourensia genus. Blackbrush is native to the Chihuahuan Desert of North America. Blackbrush is also known as American yellowtops, Helianthus cernuus.

Blackbrush displays a dense, bushy shrub growth habit, reaching up to 4 ft tall with a spread of approximately 4 ft. Blackbrush produces small yellow flowers in clusters.

Leaf size: approximately 2 inches.

Water a young or newly planted Blackbrush every 10–14 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.

Blackbrush thrives in full sun.

Flourensia cernua tolerates temperatures of 50–90°F. Blackbrush prefers humidity levels of 30–60%.

Sandy, well-draining soil mix with good aeration. Good drainage is essential for Blackbrush to prevent waterlogging, which leads to root rot and fungal issues.

Feed Blackbrush 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 and sandy, well-draining soil mix with good aeration. Avoid low spots where water collects after rain.

Blackbrush 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.

Blackbrush can spread to about 4 ft (1.2 m) and reach about 4 ft (1 m) tall. Space plants about 4 ft (1.2 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 Blackbrush 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.

Blackbrush 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.

Blackbrush can be propagated through seeds. Similar propagation techniques also apply to flourensia pringlei plant care, which shares the same genus.

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

Blackbrush 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.

Blackbrush grows outdoors in USDA Zone 12a. It survives winters down to planting zone 12a. Blackbrush is native to the Chihuahuan Desert of North America. In cooler regions, grow Blackbrush as a houseplant or bring it indoors before the first frost.