Howittia trilocularis Plant Care

Howittia trilocularis (Howittia trilocularis) belongs to the Malvaceae family within the Howittia genus. Howittia trilocularis is native to Australia.

Howittia trilocularis displays a compact, bushy shrub growth habit, reaching up to 2.5 ft tall with a spread of approximately 2.5 ft. Howittia trilocularis produces bright, showy blooms in various colors.

Leaf size: approximately 6 inches.

Water a young or newly planted Howittia trilocularis 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.

Howittia trilocularis thrives in full sun to partial shade.

Howittia trilocularis tolerates temperatures of 60–80°F. Howittia trilocularis prefers humidity levels of 50–70%. A pebble tray or humidifier helps maintain adequate moisture around the plant.

Well-draining loamy soil mix with added compost for nutrients. Good drainage is essential for Howittia trilocularis to prevent waterlogging, which leads to root rot and fungal issues.

Feed Howittia trilocularis 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 mix with added compost for nutrients. Avoid low spots where water collects after rain.

Howittia trilocularis 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.

Howittia trilocularis can spread to about 3 ft (0.8 m) and reach about 3 ft (1 m) tall. Space plants about 3 ft (0.8 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 Howittia trilocularis 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.

Howittia trilocularis 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.

Howittia trilocularis can be propagated through seeds, stem cuttings.

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Howittia trilocularis 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.

Howittia trilocularis grows outdoors in USDA Zone 13a. It survives winters down to planting zone 13a. Howittia trilocularis is native to Australia. In cooler regions, grow Howittia trilocularis as a houseplant or bring it indoors before the first frost.