Needle grasses and native grasses
Posted on 26 February, 2019 by Ivan
Distinguishing needle grasses from native grasses
Needle grasses, in particular, Chilean Needle Grass (Nassella neesiana), are becoming serious pasture and environmental weeds in south-eastern Australia, including around the Mount Alexander region. They are very invasive and form dense infestations in pastures, bushland and roadsides. They can tolerate drought and will seed prolifically, giving them a 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.
One of the biggest challenges facing successful treatment of needle grasses is identifying infestations before they become large and dominating in the landscape. Thankfully, a local community champion recently produced an information sheet on how to differentiate needle and native grasses, titled ‘Distinguishing between needle grasses and native grasses‘. The information sheet has useful photographs and identifying features of needle grasses, and compares these features to a variety of spear grasses (Austrostipa species), wallaby grasses (Rytidosperma species) and native tussock grass (Poa labillardieri). Grasses covered include Chilean, Texas and Cane Needle Grass (all members of Nassella genus), and the closely related Espartillo (Amelichloa caudata).
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.
Another helpful information sheet, ‘What to do if you find needle grass’ details first-hand experience in how best to manage these grassy weeds and prevent further spread.