Stenocarpus spp.

firewheel tree

Proteaceae

Eastern Australia, New Guinea, New Caledonia

Attracts Pollinators

SunFull Sun – Part Shade

WaterMedium

HardinessZones 9–11

Overview

Stenocarpus spp. is a genus of about 25 species of evergreen trees and shrubs in the family Proteaceae, native to rainforests and open forests of eastern Australia, New Guinea, New Caledonia, and the Malesian region. Plants range widely in size, from shrubs 6-10 feet (1.8-3 m) tall to rainforest trees reaching 80-100 feet (25-30 m) in habitat, though cultivated specimens are usually far smaller. The leaves are leathery and glossy, varying from entire and lance-shaped to deeply lobed within a single tree. The genus is known for flower clusters arranged like the spokes of a wheel; in the firewheel tree, S. sinuatus, these umbels of red-and-orange tubular flowers open on the trunk and older branches in late summer and autumn. Woody, boat-shaped follicles follow and release winged seeds. Stenocarpus spp. grows in fertile, well-drained soils in warm-temperate to subtropical climates and is frost sensitive when young. Growth is slow, and trees raised from seed may take many years to reach flowering size, with bloom often sparse in cooler or drier conditions.

Native Range

Stenocarpus spp. is native to eastern Australia, New Guinea, New Caledonia, and parts of Malesia. The firewheel tree, S. sinuatus, grows in subtropical rainforest of New South Wales and Queensland, while other species occur in drier forests and on New Caledonian soils.

Suggested Uses

Stenocarpus spp. is used as a specimen and shade tree in subtropical and warm-temperate gardens, parks, and streets, with the firewheel tree grown for its wheel-shaped flower clusters. Shrubbier species suit screening and mixed plantings. The timber of some species is used in cabinetwork.

How to Identify

Identify Stenocarpus spp. by its leathery, glossy evergreen leaves, which range from undivided to deeply lobed even on one plant, and by its wheel-like flower clusters in which the tubular flowers radiate from a central point like spokes. In the firewheel tree these clusters are red and orange and open on trunk and older wood. Woody, canoe-shaped seed pods that split to release winged seeds confirm the genus.

Appearance

Size & Dimensions

Height6' - 100'

Width/Spread6' - 25'

Colors

Flower Colors

red

orange

Foliage Colors

green

Fall Foliage Colors

no change

Bloom Information

Bloom Period

~6 weeks

Summer Fall

Flowering is mainly in late summer and autumn, roughly February to May in the Southern Hemisphere, with some variation among species. The wheel-shaped clusters open over several weeks and are visited by nectar-feeding birds. Young trees often flower sparsely until well established.

Detailed Descriptions

Foliage Description

glossy green

Growing Conditions

Sun Requirements

SunFull Sun SunPartial Shade

Requires 5-10 hours of direct sunlight daily

• Full Sun: 6+ hours of direct sunlight

• Partial Shade: 3-6 hours of direct sunlight

• Full Shade: Less than 3 hours of direct sunlight

Soil Requirements

pH Range5.5 - 7.0(Neutral)

357912

Soil Types

loam sand

Drainagewell drained

Water & Climate

Water Needs

Medium

Frost Tolerance

tender

Time to Maturity

8-10 years

Care & Maintenance

Care Guide

Stenocarpus spp. grows in full sun to part shade and prefers deep, fertile, well-drained soil with steady moisture, especially while young. Water needs are medium; the genus is not strongly drought adapted, though established trees cope with short dry periods. Soil pH from about 5.5 to 7.0 suits most species. Plants are frost sensitive when young and suit warm-temperate, subtropical, and frost-free climates, roughly USDA zones 9-11. As members of the Proteaceae, they grow poorly with high-phosphorus fertilizers. Growth is slow and the long juvenile period delays first flowering.

Pruning

Pruning is generally light and done after flowering. Formative pruning of young plants encourages a single leader and balanced canopy, while mature trees need little more than removal of dead or crossing wood. Hard cutting into bare old wood is avoided because regrowth is slow.