Weed Alert: Mexican feather grass
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|Mexican feathergrass (Agfact P7.6.60)||258.4 KB|
- Declared in NSW under the Noxious Weeds Act 1993 (Current Status)
Contacts and Further InformationIf you find this weed please help to prevent its further spread by contacting your local Council Weeds Officer or the nearest NSW Department of Primary Industries office immediately for positive identification and further assistance.
Alternatively call the NSW Weeds Hotline on
1800 680 244 or send an email to firstname.lastname@example.org
Mexican feather grass (Nassella tenuissima)
Mexican feather grass (Nassella tenuissima), is a potentially serious weed of pastures, native grasslands and woodlands. It is a highly adaptable grass that has the potential to infest up to 65% of New South Wales (NSW), causing major economic and environmental damage.
Mexican feather grass is unpalatable to stock, difficult to control and capable of growing in a variety of climates and soil types. It is able to tolerate prolonged periods of drought and can flourish in areas that are heavily grazed. Mexican feather grass is closely related to serrated tussock (Nassella trichotoma), an invasive weed of temperate grasslands, and can only be distinguished when in flower.
Mexican feather grass was initially found in some NSW nurseries, mislabelled and marketed as ‘elegant spear grass’, a name given to the native grass Austrostipa elegantissima. All known plants were destroyed at that time.
Later, in 2004, a number of plants were found and destroyed in landscaped gardens in Tamworth, Uralla and Tenterfield. It is still possible that plants could exist in gardens and nurseries, and should be destroyed if found.
During 2008, a wholesale nursery based in Victoria imported seed of ornamental stipoid grasses. It is believed that the seed was either mislabelled or contaminated with Mexican feather grass seed, which was then propagated, sold and distributed. The plants may have been sold under the names of Stipa lessingiana, S. capillata, S. capriccio or Stipa Regal Sensation.
Online overseas seed companies have also marketed the plant under various names including Stipa tenuissima, Stipa tenaccissima, elegant spear grass, white tussock, Texas tussock grass and ponytail grass.
Mexican feather grass is native to southern USA (New Mexico and Texas), Mexico, Chile and Argentina and is considered a weed even within its native range.
It is a declared weed in South Africa and has naturalised in New Zealand and California, following its spread from cultivation as a garden plant.
Mexican feather grass reproduces by seed. From mid spring to summer it germinates freely on well-drained soils where there is little competition from other vegetation. Seeds can be dispersed by becoming attached to clothing, livestock and vehicles, or from contaminated seed and fodder.
Mexican feather grass is a dense, upright tussock up to 70 cm.
Key identification features
- Leaves are 0.25–0.5 mm wide, up to 60 cm long and tightly rolled with overlapped edges. Leaves roll smoothly between the fingers like a needle, but feel coarse when sliding fingers downwards along the leaf blade. The ligule (a small, thin structure at the base of the leaf blade) is 0.5–2.5 mm long, opaque, papery and smooth.
- Flowering stems are up to 70 cm high, round, smooth and hairless, with 2–3 unthickened nodes.
- The flower head is 15–25 cm long and green or purplish in colour. An identifying feature of the plant is that the flower head does not detach from the plant and it has a leaf-like sheath that encloses its lower section.
- Seeds are 2–3 mm long and encased by two purple or reddish-brown glumes, 6–10 mm long. Another distinguishing feature is the awn, which is 4.5–9 cm long and attached centrally to the end of the seed.
If you suspect you have found Mexican feather grass, immediately contact a local council weeds officer who will assist with identification, removal and eradication.
Mexican feather grass is a Class 1 State Prohibited Weed across NSW under the Noxious Weeds Act 1993. It must be eradicated and land must be kept free of the plant. As a notifiable weed, all outbreaks must be reported to the local council within 24 hours, and the plant is prohibited from sale in NSW.
2009 edition written by Alan Maguire; prepared by Annette McCaffery and Annie Johnson; 2013 edition reviewed by Michael Michelmore; edited by Elissa van Oosterhout.
- Csurhes S (2008) Mexican feather grass (Nassella tenuissima)—Pest plant risk assessment, Queensland Department of Primary Industries and Fisheries, Brisbane
- Maguire A (2005) Mexican feather grass. NSW DPI Agfact P7.6.60
- Victorian Department of Primary Industries (2004) Landcare Notes – Mexican feather grass: State prohibited weed, Frankston.