Gahnia sieberiana, commonly known as the red-fruit saw-sedge, is a tussock-forming perennial plant in the family Cyperaceae, endemic to Australia.

[2] Gahnia sieberiana grows as a tall strappy tussock to 2 metres (6 ft 7 in) high and wide, with rough flat leaves.

[4] The tall black flowers grow in spikes from the centre of the plant and can rise another metre above the clump,[5] appearing in spring and summer.

[3] Gahnia sieberiana is found across eastern Australia, from Tasmania to North Queensland, as well as Malesia, from sea level to an altitude of 1,200 m (3,900 ft).

[12] For Australian gardens, Gahnia sieberiana has been suggested as a native replacement for pampas grass (Cortaderia selloana), which is a noxious weed there.