Nassella tussock grasses have been a pest since the 1940s, and it now densely populate the Canterbury region.
Environment Canterbury (ECan requires the removal of the tussock on land inside the sustained control zone by October 31, and by September 30 on property outside the zone.
ECan's website states that one mature plant can produce 120,000 seeds, which spread easily. The plant grows up to 70cm tall and 70cm wide, with bright green leaves when young, but dulled leaves that droop as it ages.
Nassella differs from other tussock species as it has shallot-like white stem bases and more fibrous leaves. The root system is deep and tangled, meaning removal is costly and damaging to land.
Shading caused by the tussock means it overpowers smaller, yet more integral, pastures.
Stock will not eat the tussock, making an invasion a serious economic risk to farmers.
ECan is advising people to remove the tussocks by thoroughly digging up individual plants, and saving chemicals for more extensive groups.