Detailed information sheet

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Botanical name : Nassella trichotoma and Nassella tenuissima Family : Poaceae (Gramineae) (grass) family  Common name : nassella tussock and needlegrass  Also known as : Stipa trichotoma (nassella) and Stipa tenuissima (needlegrass)   Where is it originally from? : Chile and Argentina What does it look like? : Both species look and behave nearly identically, and are tussock-forming perennial grasses, with fibrous roots from small shallot-like bases. Extremely tough, thin, round leaves (300-500 x 1 mm) do not break when pulled, are rough to touch, erect and drooping, and are light green in S. trichotoma and bright green in S. tenuissima). Membrane-like ligule (2 mm long), no auricles (ear-shaped attachments at the bases of leaves), and a small sheath that is white underneath with a brownish outer covering. Drooping flowering stems (to 1 m) with open seedheads are produced from November to January, with the seeds ripening to purple with bristles (3 cm long) that allow them to hook onto clothing and animal pelts.  Are there any similar species? : Native Danthonia species appear similar when small, but leaves are softer with hairy ligules and they break when pulled. Chionochloa and Poa species have flat-bladed leaves. Stipa neesiana, other non-native and some native Stipa species are also similar.  Why is it weedy? : Long-lived and form pure colonies, producing masses of highly viable, long-lived, well dispersed seed. Stock cannot digest them. Tolerate climate extremes from hot to cold, poor soils, damp to drought, wind, salt, fire, and damage, but are intolerant of moderate-shade and waterlogged soils.  How does it spread? : Seed is spread by wind, on livestock pelts, clothing, and boots, and by contaminated machinery and milled plantation logs. Sources of seed include farms and pine plantations.  What damage does it do? : Form pure stands in low-growing plant communities, especially in harsh sites, and prevent the seedlings of native species establishing.  Which habitats is it likely to invade? : Disturbed shrubland, tall and short tussockland, bare land, river systems, rocky and coastal areas. Could potentially spread throughout New Zealand.  What can I do to get rid of it? : 1. Grub (all year round): Remove soil from roots. Leave on site to rot down. 2. Weed wipe (dense infestations) (all year round): glyphosate (333ml/L + penetrant). 3. Spray dense spots amongst desirable broadleaved species (spring-summer): Gallant (5ml/L + crop oil). 4. Spray dense infestations only (all year round): glyphosate (15ml/L + penetrant). What can I do to stop it coming back? : Cut rootstock and roots not completely grubbed from soil will resprout, and seed bank reinfests bared, burned or sprayed areas. Fire enhances seeding.  Do not burn as fire enhances seedings, and exclude all livestock. Plant dense low cover where appropriate after control. Follow up on open sites for at least 10 years.

For more detailed botanical descriptions of weed species, check out the Plant Conservation Network's website at http://www.nzpcn.org.nz/exotic_plant_life_and_weeds/index.asp

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*The chemical control methods in this manual were devised by Department of Conservation staff for Department of Conservation operations and should not be used as a substitute for the pesticide manufacturer's label instructions. The Department of Conservation takes no responsibility for any liability or damage to any person, property or thing which may occur as a result of the use of any pesticide in accordance with the chemical control methods contained on this website.

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