Nutgrass (Cyperus rotundus L.), a plant native to India, is known as the world's worst weed . It is a member of the family Cyperaceae, which contains approximately 3000 species, of which about 220 species are important weeds . Nutgrass is cold sensitive , only growing during the warmer months and will not survive in the colder parts of Australia. It is adapted to most soil types and soil moisture regimes