Sigmoid Conospermum Plant Care

Sigmoid Conospermum (Conospermum sigmoideum) belongs to the Proteaceae family within the Conospermum genus. Sigmoid Conospermum is native to the south of Western Australia.

Sigmoid Conospermum displays an upright, bushy shrub growth habit, reaching up to 3 ft tall with a spread of approximately 2 ft. Sigmoid Conospermum produces small, tubular flowers in shades of white, pink, or purple.

Leaf size: approximately 4 inches.

Water a young or newly planted Sigmoid Conospermum 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.

Sigmoid Conospermum thrives in full sun to partial shade.

Conospermum sigmoideum tolerates temperatures of 50–80°F. Sigmoid Conospermum prefers humidity levels of 40–60%.

Well-draining sandy soil with added organic matter for nutrients. Good drainage is essential for Sigmoid Conospermum to prevent waterlogging, which leads to root rot and fungal issues.

Feed Sigmoid Conospermum 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 added organic matter for nutrients. Avoid low spots where water collects after rain.

Sigmoid Conospermum is suited to USDA Zone 9b – 11a.

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.

Sigmoid Conospermum 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 Sigmoid Conospermum 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.

Sigmoid Conospermum is frost-tender (hardy to USDA zone 9). In colder areas grow it in a container and move it to a bright, frost-free place before the first frost.

Sigmoid Conospermum can be propagated through seeds, cuttings. Similar propagation techniques also apply to smokebush plant care, which shares the same genus.

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

Sigmoid Conospermum is susceptible to aphids, spider mites, scale insects. 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.

Sigmoid Conospermum grows outdoors in USDA Zone 9b – 11a. It survives winters down to planting zone 9b. Sigmoid Conospermum is native to the south of Western Australia. In cooler regions, grow Sigmoid Conospermum as a houseplant or bring it indoors before the first frost.