Mexican feather grass

Scientific name: Nassella tenuissima
Declaration status: Class A

Mexican feather grass is not known to be present in the Northern Territory (NT).

It is not known to be naturalised anywhere in Australia at the present time. However, it has now been found in Victoria, New South Wales, Queensland and Western Australia.

Mexican feather grass is native to southern USA, Chile and Argentina.

It is similar to serrated tussock in terms of ecology and growth and has the potential to invade up to 14 million hectares in Australia, a far greater area than serrated tussock.

Each Mexican feather grass plant can produce between 70,000 and 100,000 seeds per year.

Mexican feather grass was introduced to Australia when mislabelled and sold as an ornamental plant under the names Elegant Spear Grass, Pony Tail and Angel's Hair.

In 2008, an estimated 4,000 Mexican feather grass plants were supplied and sold through retail stores in Victoria, Queensland and New South Wales.

Following prompt action by DPI officers and retailers in Victoria, suspect plants were removed from sale and a state-wide recall of Mexican feather grass plants was initiated.

It has escaped from cultivation in New Zealand and has become a weed that is continuing to spread.

For more information get the Mexican feather grass identification fact sheet PDF (522.5 KB).


Mexican feather grass poses a serious threat to Australia. It is closely related to other exotic grasses, including serrated tussock and Chilean needle grass which are both Weed of National Significance.

For more information visit the Weed of National Significance website.

Mexican feather grass could have all of the following impacts:

  • unpalatable to livestock
  • low nutrient content
  • can cause fibre-balls in the digestive tract of animals which have the potential to cause loss of condition and death
  • out competes native and pasture grasses and other vegetation
  • may affect the fire regime of an area it infests.

You should use this as a guide. There may be other plants or weeds that look similar.

  • approximately 70cm tall
  • leaves needlelike and roll smoothly between the fingers 0.25 to 0.5mm in diameter and up to 60cm long
  • flowers can appear green or purplish, can only be distinguished from serrated tussock when flowering
  • seed heads form on a long flower spike with a small pointed tip and a long bent tail 15 to 25cm long that resembles a large feather when clumped together at the end of the flower spike
  • seeds are 0.2 to 0.3cm long with bristle-like appendage that is 4.5 to 9cm long extending from the end of the seed

Mexican feather grass - habit Mexican feather grass - stems and branchesMexican feather grass - leavesMexican feather grass - flowers Mexican feather grass - fruit and seeds

If you are unsure, contact the Weed Management Branch.

If you think you may have seen Mexican feather grass in nurseries, gardens or established settings, or if you have this weed on your property, do not attempt to control it. Contact the Weed Management Branch immediately for assistance.

Last updated: 15 January 2020

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