Texas Needle-Grass (DPI Vic)

February 2000 Texas needle-grass LC0265 Linda Penhall and Rick James, (Ballarat), and Ian Faithfull, (Frankston) ISSN 1329-833X

This Landcare Note describes the weed Texas needle- Origin and distribution grass, Nassella leucotricha. Texas needle-grass is indigenous to Oklahoma, Texas and Central Mexico and has naturalised in Australia only in Common name Victoria. The weed was first discovered in 1934 in Texas needle-grass Northcote, Melbourne. It has since spread and infestations have been recorded at Taradale, near Castlemaine, Mt Botanical name Beckworth near Ballarat, and several infestations around Nassella leucotricha (Trin. & Rupr.) Pohl. Geelong and Melbourne, mostly on basaltic soils. These Synonym Stipa leucotricha Trin. & Rupr. Family Poaceae infestations occur almost exclusively on roadsides. Status Texas needle-grass is closely related to serrated tussock, one of Victoria’s worst weeds, and has the potential to cause major economic and environmental damage. Texas needle-grass can easily be overlooked because of its similarity to indigenous tussock grasses and other Nassella species such as Chilean needle-grass (Nassella neesiana) and lobed needle-grass (Nassella charruana). The known distribution is currently limited to a few small infestations around Victoria, where management programs aim to eradicate it. However the potential distribution of Texas needle-grass in Australia has been estimated to be 4.8 million hectares, with a substantial area of Victoria at risk.

Figure 2. Texas needle-grass infestation. Description Texas needle-grass is a perennial tussock-forming grass in the speargrass group (Tribe Stipeae). It grows to about 1 – 1.5 m high. The weed thrives under conditions of moderate soil disturbance and poses a threat to agriculture and native vegetation. Flowering time is from October to February. In South America, the plant is known to produce stem seeds (cleistogenes), concealed under leaf sheaths at the base of the plant that enable it to reproduce even when flowering is prevented by grazing or slashing. As yet, these have not been recorded in Australia. Stems – Erect, unbranched, to 1 or 1.5 m, mostly hairless. Leaves –approximately 30 cm long and 5 mm wide. The blades appear flat or slightly inrolled. The ligule (the small membranous appendage on the inner side of the leaf where it sheaths the stem) is 0.5-1 mm long and hairless. Figure 1. Texas needle-grass. Flowers – borne in a contracted panicle to 25 cm long.

Properties Texas needle-grass is highly invasive and can form dense infestations, particularly on poorly managed sites. It prefers open grassland sites similar to those favoured by native grassland species. Due to its invasive growth, vigorous reproduction, and potential for long distance dispersal, Texas needle-grass has the potential to further spread from these known sites. The species is known as Texas wintergrass in its native Texas where it is regarded as a plant of significant fodder Figure 3. Flowering head (panicle) of Texas needle-grass. value and is readily grazed by stock in winter and early spring. There has been no research conducted on its Seeds – Vary from a pale brown to purple in colour at nutritional value in Australia, however it is definitely an maturity. Glumes (the outermost and lowest bracts) undesirable species for Victorian grazing lands. measure 11- 15 mm long, lemma (the lower of the two The sharp, pointed seeds have been known to be carried bracts around the seed) 6-9 mm, palea (the innermost bract long distances by attaching themselves to the wool or fur bract around the seed) 1-2 mm and callus (the hardened of animals. These sharp intrusive seeds can be a hazard to extension at the base of the seed) 1-3 mm. The corona (the animals and contaminate produce. hardened ring of tissue at the apex of the lemma) is 1mm long with erect apical hairs (or slender spines), extending Management from it. These hairs are 0.6-1.5 mm long. The awn (the Suspect plants should immediately be reported to the fine, bristle-like appendage extending from the lemma) is nearest DSE office. Flowering specimens should be bent twice and is 35-60 mm long, with 10-20 mm to the collected and sent to the National Herbarium of Victoria, first bend. Birdwood Avenue, South Yarra, 3141, to confirm Roots - fibrous. identification. DSE can determine how best to eradicate new infestations. References Keith Turnbull Research Institute (1999) Chilean needle grass identification. Landcare Notes LC0256, Department of Natural Resources and Environment. Keith Turnbull Research Institute (1999) Mexican feather grass. Landcare Notes LC0263, Department of Natural Resources and Environment. Keith Turnbull Research Institute (1999) Lobed needle grass. Landcare Notes LC0264, Department of Natural Resources and Environment. McLaren, D.A., Stasjic, V. and Gardener, M. (1998) The distribution and impact of South/North American stipoid grasses (Poaceae: Stipeae) in Australia. Plant Protection Quarterly 13(2), 62-70. Shepherd, R.C.H. and Richardson, R.G. (Eds.) (1998) Proceedings of the Nassella Workshop. Plant Protection Quarterly 13(2), 59-103. Figure 4. Texas needle-grass seeds Walsh, N. (1994) Poaceae. Pp. 356-627 in Walsh, N.G. and Entwisle, T.J. (Eds.) Flora of Victoria Volume 2. Ferns and Allied Plants, Conifers Similar species and Monocotyledons. Melbourne, Inkata Press. Four other species of Nassella are naturalised in Victoria: Walsh, N. (1998) Identification of South American tussock weeds. Plant Protection Quarterly 13(2), 59-62. N. trichotoma (Nees) Hack. ex Archav., serrated tussock N. neesiana (Trin. & Rupr.) Bark., Chilean needle-grass Acknowledgements N. hyalina (Nees) Barkworth, cane needle-grass David McLaren provided information and comment. N. charruana (Arech.) Barkworth, lobed needle-grass Photographs by Linda Penhall. They can be distinguished from Texas needle-grass as follows. Serrated tussock seeds lack a corona. The seed of Chilean needle-grass is larger than that of the Texas This publication may be of assistance to you but the State of Victoria and its officers do not guarantee that the publication is without flaw needle-grass - the length of the awn is almost double, 60- of any kind or is wholly appropriate for your particular purposes 90 mm compared to 35-60 mm. The lemma of cane and therefore disclaims all liability for any error, loss or other needle-grass measures 3.5-6 mm, usually much smaller consequence which may arise from you relying on any information in than that of Texas needle-grass, which measures over 6 this publication. mm. Lobed needle-grass has distinct large whitish lobes on its corona.