New noxious weed found at Tamworth

The State's first incursion of Mexican feather grass (Nassella tenuissima) has been found in a landscaped garden at Tamworth in the State's north-west.

The positive identification of plants found by Tamworth Regional Council weeds officers was made by NSW Department of Primary Industries in consultation with the National Herbarium in Sydney.

Mexican feather grass is a notifiable (W1) noxious weed closely related to serrated tussock (Nassella trichotoma), a major pasture and environmental weed in temperate Australia.

NSW Department of Primary Industries Noxious Weeds Coordinator, Sydney Lisle, said it had been established that the potentially serious new weed had been planted due to a mislabelling error.

"Investigations reveal that plants have been mislabelled and marketed in some nurseries in NSW as 'elegant speargrass', a name given to the native grass Austrostipa elegantissima," Mr Lisle said.

"At this stage there are no other reports of Mexican grass naturalising elsewhere in NSW, but there is a high probability that this has occurred due to its similarity to other species, especially serrated tussock."

He said if Mexican feather grass becomes naturalised it could have a wider range than serrated tussock, with up to 65 percent of NSW likely to be at risk.

"We believe the Tamworth garden started with four plants, but the number had increased to 269 when Council weeds officers moved in to remove and dispose of them some eight years later.

"Most were found in the lawn area, which demonstrates that the grass is hard to eliminate, even with successive mowing.

"For this reason, the area will be closely monitored for several years so that any new plants from seeds that have been shed over the years are disposed of."

Like serrated tussock, Mexican feather grass is a densely tufted perennial tussock, but differs from serrated tussock in that its seed head does not always fully protrude from the surrounding sheath at maturity.

In addition, the awns (the long bristle at the end of the seed) on Mexican feather grass are longer (5 to 9 cm) and attach at the centre of the seed while serrated tussock awns are 2 to 3.5 cm and are offset in their attachment to the seed.

Mr Lisle said anyone who suspects they have Mexican feather grass plants should contact their local weeds officer to have the plants identified.

DPI is providing training in the identification of Mexican feather grass for Council weeds officers throughout the north-west in the coming week.

Further information on Mexican feather grass is available from local Councils or the NSW Noxious NSW Invasive Plants and Animals Enquiry Line.

Media contact: NSW DPI Weeds Agronomist Bob Trounce.

Issued by: Annette Cross, NSW DPI Tamworth

Media note: High resolution images are available from Annette Cross