Rhizomatous, tufted perennial, grass-like or herb, 0.15-1.75 m high. Fl. green/green-purple, Oct to Dec or Jan to Apr. Sand, loam, laterite. Moist habitats (claypans, rivers, ditches).
Alternative Names. Dallis grass.
General Biology. Growth form. Grass. Life form. Perennial, caespitose/shortly rhizomatous. Reproduction. Seed, short rhizomes. Dispersal. Seed spread by animals, clothing, shoes, water, wind, machinery. Vegetative spread by earth-moving, cultivation, inappropriate planting. Photosynthetic Pathway. C4. Toxicity. Not toxic itself however fungus-infected seedheads pose a threat to animal health. Fire response. Will quickly resprout from rootstock when conditions become favourable.
Notes. Widely naturalised particularly in sub-tropical and warm temperate climates, especially those with summer rainfall. Common in all Australian states in pastures, roadsides, gardens or lawns. A major weed of wetland edges, wet native grasslands and road drains. Susceptible to frost, however winter dormancy may enable it to survive frost in some areas. For active growth requires high temperatures, irrigation and high soil nitrogen levels. Has low salintiy tolerance however a deep root system confers significant drought tolerance once established. Flowering commences in early to mid summer, coinciding with a marked slowing in vegetative growth. Flowering continues through autumn, with little foliage produced until the following spring. Seed production is inhibited at temperatures below 13°C. Viability is often low and affected by ergot infection. Seed is sticky and is easily unintentionally dispersed. Disturbance events that create gaps (such as flooding and heavy grazing) promote recruitment. Vegetative spread is extremely slow. There are at least 5 different cultivars and 8 biotypes, with significant variation in seed production, quality and growth rates between genotypes. Can form hybids with Paspalum urvillei.
Additional information. Origin. South America. History of use/introduction. Summer pasture, erosion control particularly where there is water movement. Similar exotic species. Paspalum urvillei.
Suggested method of management and control. Cut out small populations and isolated plants, ensure rhizome removal. Remove seed heads for safe disposal. At early head stage spray with glyphosate 10 ml/L. For established actively growing adult plants spray with Fusilade® Forte 16 ml /L + wetting agent or for generic fluazifop-p (212g/L active ingredient) 8ml/L+ wetting agent. Older stands can also be controlled with 1% glyphosate, preferably pre- or early flowering. Alternatively, cut near ground level and immediately wipe with 10% glyphosate. A repeat application may be required for well established plants. Follow-up control of seedlings with 2 ml/L Fusilade® Forte + wetting agent or for generic fluazifop-p (212g/L active ingredient) 1.2ml/L+ wetting agent. Use hygiene practices - clean machinery and footwear after working in infested areas. Mowing and slashing will remove flowering heads but will not control established plants and can spread seed. Strategic use of fire may be useful in suppressing this species. Following any fire event is an optimal time to undertake control. Read the manufacturers' labels and material safety data sheets before using herbicides. For further information consult the Australian Pesticides and Veterinary Medicines Authority to determine the status of permits for your situation or state.
Legend: Y = Yes, regularly, O = Occasionally, U = Uncertain, referred by others but not confirmed.