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Casuarina cunninghamiana
river sheoak
Overview
Casuarina cunninghamiana is a tall evergreen tree native to eastern and northern Australia, reaching 50-115 feet (15-35 m) with a straight trunk and drooping, needle-like green branchlets. What appear to be pine-like needles are actually jointed photosynthetic stems; the true leaves are reduced to rings of tiny scale teeth at each joint, usually 8-10 per whorl. The species typically grows along permanent rivers and streams, where its roots stabilize banks. It is actinorhizal, fixing atmospheric nitrogen through a symbiosis with Frankia bacteria, which lets it colonize poor soils. Trees are usually dioecious: male trees bear rusty-brown pollen spikes at the branchlet tips, while female trees carry small red flowers that develop into woody cones 0.3-0.5 inch (7-12 mm) long holding winged seeds. Bark is grey-brown and finely fissured. The tree casts dense shade and sheds quantities of branchlet litter, and its roots can be aggressive, so it has become an invasive weed in Florida and parts of Africa.
Native Range
Native to eastern and northern Australia, following permanent watercourses from New South Wales and Queensland to the Northern Territory and Western Australia.Suggested Uses
Planted for riverbank stabilization, windbreaks, and shade in large rural landscapes, and grown for firewood and erosion control. The dense canopy suits broad parkland and farm plantings. Its size, litter, and aggressive roots limit use in urban or small gardens.How to Identify
Appearance
Size & Dimensions
Height50' - 115'
Width/Spread20' - 40'
Bloom Information
Flowers are small and wind-pollinated, appearing mainly in winter and early spring, around July to September. Male trees turn rusty-brown at the branchlet tips as pollen is shed, and female trees bear small red flowers. Woody cones develop and ripen over the following months.
Detailed Descriptions
Foliage Description
greenGrowing Conditions
Sun Requirements
Requires 6-12 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