Mexican feather grass

Mexican feather grass is a declared Class A and Class C weed.

Another name for this plant is Nassella tenuissima.

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, don't attempt to control it. Contact the Weed Management Branch immediately for assistance.

Mexican feather grass - infestation

Identification

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

If you are unsure, contact the Weed Management Branch.

Habit

These features describe the habit of this plant:

  • densely tufted perennial tussock
  • about 70cm tall
  • very similar in appearance to serrated tussock.

Mexican feather grass - habit

Stems and branches

Mexican feather grass - stems and branches

Leaves

These features can identify the leaves:

  • needlelike and roll smoothly between the fingers
  • 0.25 to 0.5mm in diameter
  • up to 60cm long
  • have serrations which can be felt when sliding fingers down the length of the blade.

Mexican feather grass - leaves

Flowers

These features can identify the flowers:

  • can appear green or purplish
  • can only be distinguished from serrated tussock when flowering.

Mexican feather grass - flowers

Seed heads

These features can identify the seed heads:

  • seeds form on a long flower spike
  • seed heads are 15 to 25cm long
  • seeds have a small pointed tip and a long bent tail
  • resembles a large feather when clumped together at the end of the flower spike.

Seeds

These features can identify the seeds:

  • 0.2 to 0.3cm long
  • bristle-like appendage that is 4.5 to 9cm long extending from the end of the seed.

Mexican feather grass - fruit and seeds

Impact

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.

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.

Habitat and distribution

Mexican feather grass is not known to be present in the Northern Territory. 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 4000 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.

Control

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: 27 June 2017