Why is it a pest?

What does it look like?

• Nassella tussock can grow up to one metre tall.
• It is a tufted, tussock grass with a swollen stem. 
• It has dense white fibrous roots. Roots are deep, matted and clumped together and resemble shallots.
• Over time Nassella tussock forms dense patches and can turn the area into a monoculture of Nassella.
• Nassella tussock has small, purple-pink-red, oval seeds that are dispersed by the wind and can travel over kilometers in the right conditions.
• It has fine, tightly rolled, light green or yellowish-green leaves feel needle-like and very tough. 
• Nassella has poor nutritional value, stock cannot digest this grass as it can form balls in their stomachs.
• It flowers with purple-pink-red seeds during November-December period and each mature plant can produce up to 100,000 seeds annually. Seeds can remain dormant in soil for up to 20 years.

It can be hard to tell the difference between Nassella tussock and other tussocks, but a good way to test the difference is by running your fingers down the leaves, if the texture is rough it could be Nassella tussock.

Duntroon, Kurow and Otematata have been the locations of several new and significant Nassella infestations recently and ORC’s biosecurity team have concerns that there could be a significant number of unknown plants in the area leading to future widespread outbreaks. We’re appealing to landowners, stock agents and those in the agricultural industry to keep an eye out for signs of Nassella on rural properties. 

Closely related plants to Nassella (trichotoma) that ORC would also like to know about in the Otago region are Chilean Needle Grass (Nassella neesiana) and Mexican Feather Grass (Nassella tenuissima). 

Otago covers a huge area, so we really need the public’s help with this one.

If you think you have seen Nassella tussock anywhere in the Otago region, email biosecurity@orc.govt.nz or call 0800 474 082.

What are the rules?

How can I control it?

Management programme