Tufted perennial, grass-like or herb, 0.3-0.7 m high. Fl. green/purple, Oct to Dec or Jan to Mar or Aug. Peaty black, brown or grey sand, red sandy clay. Swamps, creek edges, disturbed areas.
Beard’s Provinces: South-West Province.
IBRA Regions: Jarrah Forest, Swan Coastal Plain, Warren.
IBRA Subregions: Dandaragan Plateau, Northern Jarrah Forest, Perth, Southern Jarrah Forest, Warren.
IMCRA Regions: WA South Coast.
Local Government Areas (LGAs): Albany, Armadale, Augusta-Margaret River, Bayswater, Bridgetown-Greenbushes, Bunbury, Busselton, Cockburn, Collie, Dardanup, Denmark, Donnybrook-Balingup, Gingin, Harvey, Joondalup, Kalamunda, Manjimup, Mundaring, Nannup, Perth, Plantagenet, South Perth, Swan, Wanneroo, Waroona.
Alternative Names. Common velvet grass, soft meadow grass.
General Biology. Growth form. Grass. Life form. Perennial, caespitose. Reproduction. Seed, tillering. Dispersal. Wind, water, birds, mammals, possibly ants, machinery and vehicles. Photosynthetic Pathway. C3. Toxicity. Causes allergic reactions in humans, poisonous to mammals. Seedbank persistence. 3 to 9 years. Fire response. Likely killed by fire, but occasionally resprouts. Soil-stored seed may survive and germinate.
Notes. Naturalised in east Asia, New Zealand, North and South America. Can be a serious weed of freshwater wetland margins. Forms dense stands and has semi-prostrate or prostrate rosette shoots, allowing it to have an aggressive smothering effect on other flora. Tolerates a wide range of conditions but is most invasive in wet soils in sunny or semi-shaded sites. Can survive moderate drought. May disappear in dry years and become abundant in wet years. Susceptible to severe frost. Exhibits considerable variation in morphology and growth habit, allowing it to successfully colonise different habitats. Able to compete with earlier emerging annual grasses and can still access soil nutrients amongst high densities of other grasses. Produces prolific seed. Relatively deep rooted. May have allelopathic effects. Foliage is tolerant to salt (sea) spray but intolerant of saline soils. Agricultural cultivars and natural hybrids are formed with H. mollis.
Additional information. Origin. Northern Africa, temperate Asia, Europe. History of use/introduction. Contaminant of cereal seed, pasture grass, land stabilisation. Similar exotic species. Anthoxanthum odoratum, Holcus mollis.
Suggested method of management and control. Remove isolated plants before they set seed. Spray glyphosate 0.5% in spring or when the first seed head appears for optimal translocation to roots. Regular slashing reduces its vigour, but should not be done while plants are seeding. Severe defoliation and repeated herbicide treatment provide the best control. Controlled burning in spring or autumn can be a potential useful tool for suppression. 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.
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Western Australian Herbarium (1998–). FloraBase—the Western Australian Flora. Department of Biodiversity, Conservation and Attractions. https://florabase.dpaw.wa.gov.au/