Controlling nassella tussock

Nassella tussock is an invasive grass that is spreading in Canterbury. It displaces other grasses leaving pasture unpalatable to stock. We are using specific control measures to prevent the spread and reduce the impact on the land and people's livelihoods.

Nassella tussock in Canterbury

In Canterbury, there are currently more than 1450 properties where nassella tussock has been found, or has previously been found. This covers over 400,000 hectares.

We are working with the community and landowners to identify nassella tussock, control and prevent seeding, find new infestations, prevent its spread and reduce impacts on production. This a challenging job as mature plants can produce up to 100,000 seeds. These seeds are dispersed to neighbouring land by wind, water, stock, clothing and machinery.

While most seeds released annually last only one to two years on the ground, some can last much longer. It can take three-to-four years after a seed has germinated for a plant to grow large enough to be detectable.

Nasella tussock

The dense nassella tussock perennial

Nasella tussock

Fine, wiry leaves rough to the touch

Nasella tussock

Red/pink seeds usually visible from October–December.

Read more about nassella tussock (Nassella trichotoma), where it originated, how to spot it, conditions it thrives and why it's a problem, on our managing plant pests webpage.

Get ahead of nassella tussock spread

To sustainably manage nassella tussock throughout the region, land occupiers must annually search their land to identify and eliminate plants. 

Search and eliminate nassella tussock

Some land is more susceptible to nassella tussock infestation, this includes north-facing hillsides and/or free draining soils where dry conditions or pastures open up each year. In these sites, with less compeition from other pastures nassella tussock can flourish.

Even if nassella tussock is not known to be present on land you manage, we recommend you become familiar with identifying plants and be on the look out for it, especially during October–December when seeding makes it easier to identify.

If you find nassella tussock on your property, you will need to dedicate time and/or resources every year to systematically search for and eliminate it, especially in highly susceptible areas. 

Video on getting ahead of nassella tussock spread

 Video: Get ahead of nassella tussock spread

We recommend you inspect your property regularly. Find out what to look out for on our managing plant pests webpage. We inspect properties every year to ensure that land occupiers who know they have nassella tussock are meeting their obligation to control it. 

We recommend you create a nassella tussock map of your property, or work with a contractor to do so. While you will need to search your property annually, a map ensures you can focus your efforts on higher density areas. A map will help keep track of areas where plants have been removed, note progress each year, and identify higher density 'hot spots'.

Seek advice

Our biosecurity team is available to provide advice on nassella tussock identification, control and management for all landowners in Canterbury.

If you have any questions, or would like an early inspection or control work, contact Environment Canterbury on 0800 324 636 or email biosecurity@ecan.govt.nz.

Report sightings

If you think you have seen nassella tussock fill out a report online.

Ways to eliminate nassella tussock

To comply with the Canterbury Regional Pest Management Plan (2018–2038), all Canterbury land occupiers are required to remove nassella tussock annually before it seeds. Plants need to be eliminated by 30 September for most properties in Canterbury, or 31 October for high-density infestations in the Hurunui district.

Book contractors early

If you need a contractor to carry out nassella tussock control on your property, we recommend that you book them several months before you need the work completed.

Timing is important. All control work needs to be completed before the plants seed and spread.

List of contractors known to undertake Nassella tussock control 2022 (PDF File, 1.47MB)

Hand removal: grubbing

Digging our nassella tussock with a hand tool, or 'grubbing' is the most common removal method. You must remove all of the root system, making sure not much soil is left on the grubbed plant, otherwise they will continue to grow and reattach to the ground.

Always carry a grubber with you to pick up any isolated plants you may come across.

Chemical removal: weed treatment

Herbicide treatment can be an effective and efficient way to reduce dense infestations. These can be applied by hand, ground or aerial boom. Active ingredients registered for the control of nassella tussock include glyphosate (short-term knock down) and sodium flupropanate (root-absorbed residual herbicide, currently not in production). Always read labels and follow instructions and check your chemical application will be compliant with your regional plan/s.

Nassella tussock resources