Nassella tussock affects production values by reducing pasture quality and it also affects environmental values by displacing native species in tussock grassland. So far, nassella tussock has only been found in the Roxburgh, Alexandra, Cardrona and Waitaki Valley areas.

Nassella tussock looks other tussock grass. It is a tufted, tussock grass with a swollen stem. Its fine, tightly rolled, light green or yellowish-green leaves feel needle-like and very tough. The plants stand up straight when young but start drooping with age and grow up to 70cm high and 80cm wide. It flowers in October and has a purplish tinge. Each mature plant can produce up to 100,000 seeds each year. Roots are deep, matted and fibre-like. It can be hard to tell the difference between nassella tussock and other tussocks a good way to test the difference is by running your fingers down the leaves; if the texture is rough it’s probably nassella tussock.

Everyone in Otago must eliminate nassella tussock on the land that they occupy.

Please let us know if you’ve spotted nassella tussock by calling ORC on 0800 474 or emailing biosecurity@orc.govt.nz.            

For low numbers the best control method is to grub the plant out, removing soil from the roots and leaving the plant to rot down. You can spray thicker infestations; get in touch with our biosecurity team at biosecurity@orc.govt.nz for advice on this.