Shining the spotlight: Chilean Needle Grass in our region
Posted on 8 December, 2022 by Ivan
Chilean Needle Grass (Nassella neesiana) is becoming a serious pasture and environmental weed in south-eastern Australia, including around the Mount Alexander region. These introduced spear grasses are very invasive and form dense infestations in pastures, bushland and roadsides, with a number of infestations known around Castlemaine and surrounds. They can tolerate drought and will seed prolifically, giving them great potential to spread and over-run existing vegetation. It has been estimated that the potential distribution for Chilean Needle Grass alone exceeds 40 million hectares across Australia.
Spear grasses are characterised by a seed with a sharp tip and a long ‘tail’ attached, giving them their spear grass name. Within the Mount Alexander region we have both native spear grasses and a handful of introduced species. One of the biggest challenges facing the successful treatment of needle grasses is identifying infestations before they become large and dominating in the landscape. Thankfully, one of our unsung local heroes, Margaret Panter, has been working on another brochure in her series on recognising and treating these invasive species. This latest guide provides photos, illustrations, descriptions and treatment options. Margaret has been surveying sites for invasive grasses for many years, diligently working to treat infestations before they become out of control.
To view and download Margaret’s brochures:
Warmer weather and the arrival of spring triggers grasses to flower, making them easier to identify. Due to the late arrival of the sunshine this year, now is a perfect time to be out looking for this species. During the warmer months, needle grasses produce large amounts of unpalatable flower stalks with little leaf material, resulting in a severe reduction of stock carrying capacity. A dense infestation of needle grass can carry up to 15,000 seeds per square metre beneath infestations. These seeds can remain viable for over ten years and can spread via livestock, machinery and disturbance.
The presence of Chilean Needle Grass may reduce land value. During the warmer months, large amounts of unpalatable flower stalks are produced, with very little leaf material, resulting in a severe reduction of summer stock carrying capacity. The vigour of Chilean needle grass can be partly explained by its efficient system of seed production.
Thank you for your hard work Margaret, in preventing the further spread of this declared noxious weed across the landscape.
Another helpful resource is the following video about how to identify this invasive grass (courtesy of the Marlborough District Council in New Zealand).