It is a dioecious tree that often forms root suckers and has fissured and scaly bark, spreading or drooping branchlets, the leaves reduced to scales in whorls of 12 to 20, the fruit 9–18 mm (0.35–0.71 in) long containing winged seeds (samaras) 3.5–5.0 mm (0.14–0.20 in) long.

The female cones are on a peduncle 3–12 mm (0.12–0.47 in) long and sparsely covered with soft, white to rust-coloured hairs when young.

[2][4][5][6] Casuarina glauca was first formally described in 1826 by Kurt Sprengel in Systema Vegetabilium from an unpublished description by Franz Sieber.

[4][13] Swamp she-oak is found along Australia's east coast from Yeppoon in central Queensland to Bermagui in southern New South Wales.

This tree then acts to turn shallows into land by preventing erosion and collecting material among its roots.

[14] Casuarina glauca is an actinorhizal plant producing root nitrogen-fixing nodules infested by Frankia.

[13] C. glauca trees drop large amounts of litter, mainly old cones and branchlets, which eventually rots down and enriches the soil unless removed by a flood event.

[18] Understory plants recorded from swamp oak groves include Juncus kraussii, Baumea juncea and Sporobolus virginicus on sandier soils and Apium prostratum, Carex appressa, Goodenia ovata, Juncus kraussii and Phragmites australis and the vine Parsonsia straminea on clay soils.

A significant inconvenience in urban settings is that its roots can invade underground water and sewer pipes if these are within 15 m (50 ft) of the tree.