Serrated tussock is a perennial (living longer than one year) grass that is native to the South American countries of Argentina, Chile, Uruguay and Peru. It can grow up to 60 centimetres in height and 25 centimetres in diameter around the base of the plant. When in flower, the drooping seed heads of serrated tussock can give the plant an overall diameter of up to 75 centimetres.
The height of plants can vary depending on soil fertility and location. Plants growing in fertile soils are capable of growing to 60 cm high while plants growing in infertile conditions are more likely to reach a height of only 15 cm. In grazing situations, serrated tussock can be reduced to small tufts of erect foliage.
Serrated tussock growing in Victoria will generally be smaller in height than serrated tussock growing in NSW, ACT or Tasmania.
The colour of serrated tussock varies from green during summer to yellow-green in winter. When in seed, the plant takes on a purple hue, due to the coloration of the seeds.
It has an extensive network of fibrous roots which exist mostly in the top 20 cm of soil, although some do occur deeper. They are dense, wiry and fibrous, making serrated tussock very difficult to pull out even when small.
At present, there appears to be two different strains of serrated tussock growing in Australia. While they are genetically the same, some features of the plant may differ.