This perennial herb grows to a height of 1.5 m and grows in large colonies where it occurs naturally. Its leaves are tough, round and spine-tipped, and the sheath is shiny black. The purplish brown flowers appear between October and February and are topped by spine-tipped bracts. It can grow in many soil types ranging from sandy soils to clay provided there is enough water. It is also used to make traditional mats. The name is derived from the Latin jungere=to tie together, bind; referring to the ancient practice of using rushes to bind into ropes.