Nassella tenuissima

Mexican feather grass

Family: Poaceae

Origin: South America

Mexican Feather Grass in seed.
A dense tussock grass from South America growing up to 70 cm tall. Flowers are light and feathery and seed heads droop as they mature.
Photo credit: Antonie van den Bos,

Regional Pest Management Plan (RPMP) status

  • National Pest Plant Accord Species
  • Whole region — Eradication

View more about the RPMP statuses

General description

Perennial, densely tufted tussock grass < 70 cm tall. Flowerhead is feathery, erect when young, weeping when mature and borne in spring. Seeds are rough-coated with a tufted hair at base.

What you need to know

To help protect our environment:

  • You must not breed, distribute, release or sell Mexican feather grass. As Mexican feather grass is a National Pest Plant Accord species, these restrictions apply within the Auckland region and across the whole of New Zealand.
  • You must not plant Mexican feather grass within the Auckland region.

Auckland Council will control Mexican feather grass at all sites where it is known to occur.

If you see Mexican feather grass anywhere in the Auckland region, please report it to Auckland Council at


Pastures, open and disturbed habitats, grasslands, coastal areas, roadsides, wasteland.


Seeds dispersed by wind, water and attachment to animal pelts. Human-mediated dispersal through contamination of clothing, footwear and machinery.

Impact on environment

Potential to outcompete native plants in coastal habitats and affect native fauna by altering habitat structure. Unpalatable to livestock and selective grazing may displace valuable pasture species.


Recommended approaches

Do not attempt to undertake control of this species. Please report to Auckland Council.

Caution: When using any herbicide or pesticide please read the label thoroughly to ensure that all instructions and safety requirements are followed.

Mexican Feather Grass heavy with seed.
Seeds can be spready by the wind, or catching on clothing and animal fur. Seeds have hairy bases to catch on anything moving passed.
Photo credit: Sara Brill, Environment Bay of Plenty
Close up of Mexican Feather Grass flowers.
Hardy grass that tend to grow in open and dry areas with low soil fertility. Can potentially out-complete native coastal grasses.
Photo credit: Antonie van den Bos,