Weed of the Week: Chilean needle grass

Published on 30 September 2024

Welcome to week two of Weed of the Week for the 2024/25 spring and summer season. Through this series of articles, Council provides the Snowy Monaro community with information and advice on new, emerging and established invasive plant species threatening our region.

Whether you’re living on the land, living in town, or just passing through – we all have a part to play in protecting our natural environment and agricultural land from invasive plants and weeds.

This week we’re focusing on Chilean needle grass. Chilean needle grass is a perennial, grassy weed closely related to serrated tussock. It is renowned for both its insidious nature and its ability to invade native and introduced pastures. Being so difficult to detect and identify, this highly invasive species can often go unnoticed in pastures for many years before being detected.

Image courtesy of Emily Griffin.

Chilean needle grass is most distinctive during late winter with its winter green growth and frosted tips. As spring pasture growth returns, it blends in amongst other vegetation and becomes very difficult to identify until seeds develop in the warmer months.

Chilean needle grass has been present in southeast NSW for over 50 years, and is widespread and prolific in many areas to the north of the Snowy Monaro. Owing to this close proximity, the movement of stock, vehicles and other equipment poses a particular threat to the spread of this weed in our region.

While the Snowy Monaro region does not have the same level of infestation as its northern counterparts, it is not without its fair share of problems. Because of its insidious nature, as more people become familiar with the weed the more likely infestations are to be reported. Recorded infestations can be found by clicking on the map link at https://weeds.dpi.nsw.gov.au/Weeds/ChileanNeedleGrass.

As the name suggests, Chilean needle grass (Nassella neesiana) is native to Chile and other South American countries. In Australia, it is recognised as a Weed of National Significance due its potential to invade and dominate natural ecosystems.

Why Chilean needle grass is a problem:

It is highly invasive, producing both conventional seed heads as well as stem seeds at nodes under the leaf sheath. Seeds remain viable in the ground for many years. The persistent seed bank makes Chilean needle grass extremely difficult to control.

Chilean needle grass exhibits similar characteristics to other local grass species, in particular fescue. When kept short and fresh it is quite palatable and often preferentially grazed by livestock and native animals, making it very difficult to identify in a pasture situation until large patches appear.

Left unchecked, it can out-compete and dominate native vegetation, reducing biodiversity. This is compounded by the hardiness of the species, with adult plants long-lived and able to withstand even the toughest of conditions.

The sharp, corkscrew-like seeds have the potential to injure animal’s eyes and cause carcass damage in a grazing situation. Seeds are readily dispersed in fodder and on animals, vehicles, and machinery.

What you can do:

• With all weeds, prevention is the best control option. Maintaining a vigorous perennial ground cover at all times will inhibit establishment of Chilean needle grass.
  
  
• Don’t panic if you identify Chilean needle grass on your property. It can be managed using a combination of tools.
  
  
• Identification is key – learn how to identify Chilean Needle Grass and understand best management practices.
  
  
• Contact Council if you suspect you’ve found Chilean needle grass. Council’s biosecurity team provide a free onsite weed identification and advisory service.
  
  
• Control incursions on your land swiftly, particularly in your high quality grasslands. The likelihood of eliminating this weed once established is very slim.
  
  
• Control options include crop rotation, pasture management, herbicide application and strategic grazing.
  
  
• Control plants before they set seed – this will reduce the likelihood of further infestations from establishing.
  
  
• Manage livestock grazing carefully during the summer months when plants may be seeding.
  
  
• Limit livestock and vehicle movements between infested paddocks and ‘clean’ paddocks.
  
  
• Avoid purchasing fodder from areas with known Chilean Needle Grass infestations

Council is here to help. If you have questions about Chilean needle grass, or any other weeds on your property – contact our specialist biosecurity officers for advice and assistance. Call 1300 345 345 or email council@snowymonaro.nsw.gov.au

Can’t identify a weed? Send in some photographs or arrange a free onsite inspection and one of our staff will promptly respond.

Download the free NSW WeedWise app for detailed information on how to identify and manage weeds. Visit www.dpi.nsw.gov.au/biosecurity/weeds

Visit the Department of Primary Industries (DPI) website for information on weed control methods – www.dpi.nsw.gov.au/biosecurity/weeds/weed-control

For more information about weeds and biosecurity in the Snowy Monaro, visit our website: www.snowymonaro.nsw.gov.au/Environment-Waste-and-Weeds