Cyperus has become a significant weed of crops of the East African highlands, in particular Kenya. As it is a weed in overseas agricultural areas with climatic and environmental conditions similar to those that occur in Australia, it is seen as a potential threat to Australia’s environment and agricultural productivity.
Cyperus teneristolon is native to Ethiopia and neighbouring countries, extending to South Africa. The only known occurrence of Cyperus in Australia invades a 2 km section of the Yosemite Creekin the Minnehaha Reserve of the BlueMountains, New South Wales. It was first recognised as naturalised in Australiain February 2000, believed to be sourced from a refuse tip upstream of the current infestation.
Cyperus is thought to have been introduced into the Australian natural environment by the dumping of garden plants at the Blue Mountains refuse tip. However, no source plant has ever been found. Cyperus is capable of spreading vegetatively, by its rhizome and stolon systems, and by seed. Its invasion of Yosemite Creek downstream from its source may have been via the movement of seed carried in the water. The whole spike will fall as one unit and eventually release the fruit (a nut) and the enclosed seed.
Cyperus teneristolon is a perennial sedge which grows to 500 mm high. Sedges are evergreen plants with triangular stems that generally grow in damp areas. The species name teneristolon refers to the long and delicate stolons (ground-covered stems) that sprout new plants.
The main flowering spike is egg-shaped, purple to black in colour, and made up of many tiny flowers (an ‘inflorescence’), or spikelets, to 3 mm long with a distinctive point.
The shape and colour of the inflorescence distinguishes C. teneristolon from all other sedge species.
The fruit, produced from the mature flower, is dry, contains one seed and does not split open to release the seed when on the plant.
The leaves are 1–3 mm wide, have roughened margins and are bright green in colour.
The roots are fibrous and the plant has an extensive rhizome system (underground stems) which supports its regrowth each season and helps it spread.
Both native and naturalised populations of Cyperus suggest that it prefers highland areas with soils that are sandy and poor in nutrients.
CRC for Australian Weed Management: Tanya McLean (Bushcare Coordinator for the Blue Mountains), John Hosking (NSW Agriculture/Weeds CRC), Jeremy Bruhl (University of New England).
Because Cyperus has naturalised in only one known location, it can still be eradicated. Any new outbreaks should be reported immediately to your local council weed officer. Do not try to control Cyperus without their expert assistance. Control effort that is poorly performed or not followed up can actually help spread a weed and worsen the problem.
Cyperus (Cyperus teneristolon) is not declared in NSW under the Noxious Weeds Act 1993.