Glyceria maxima (Hartm.) Holmb.
Water Meadowgrass

Management Notes (for the Swan NRM Region)

Alternative Names. Reed meadow grass, reed sweet grass.

General Biology. Growth form. Grass. Life form. Perennial, rhizomatous. Reproduction. Largely by rhizomes and stems, possibly seed. Dispersal. Water, machinery, vehicles, footwear, livestock. Photosynthetic Pathway. C3. Time to first flowering. 2 years. Toxicity. Accumulates toxic levels of hydrocyanic acid in young shoots that has resulted in cattle deaths. Seedbank persistence. Has varying levels of dormancy, short to medium, up to 5 years. Fire response. Resprouts.

Notes. An aggressive species that can form dense impenetrable stands over large areas. Found mostly in habitats subject to natural disturbance such as rivers, streams and wetlands. Mostly reproduces from rhizomes in flowing and still water. Prefers well aerated water, with growth and reproduction slowing as conditions become anaerobic. Forms monocultures that reduce plant species diversity, can restrict access to waterways, impede water flow, cause local flooding, convert sections of fast-flowing aerobic streams into partially anaerobic swamps and accelerate siltation. Reduces native macroinvertebrate diversity and creates suitable environments for mosquito larvae and other pests. Temperate regions are most susceptible. Prefers sites with high phosphorous and nitrogen content low in organic carbon. Has strong allelopathic effects, inhibiting germination of other species. Mild tolerance to salinity. Has a lifespan of 3–10 years.

Additional information. Origin. Temperate regions of Europe and Asia. History of use/introduction. Fodder for cattle, ornamental, recovery of nutrients from wastewater.

Suggested method of management and control. Manually remove small plants. In and around waterways use Roundup Biactive® (360g/L) 10 ml/L in late summer to autumn. Ensure complete foliage cover and avoid run-off or spray drift entering water. Away from waterways (such as dry drains and roadsides) apply 1% glyphosate (360g/L) + Pulse® or Fusilade® Forte 16 ml/L + wetting agent or for generic fluazifop-p (212g/L active ingredient) 10ml/L + wetting agent towards the end of summer. Control young plants at an early growth stage, before they have become established or produce seed. For best results spraying in both summer and autumn is recommended, with follow-up needed over at least two or three seasons. 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.

Management Calendar

Legend: Y = Yes, regularly, O = Occasionally, U = Uncertain, referred by others but not confirmed.

 

References

• Bodelier, P.L.E., Libochant, J.A., Blom, C.W.P.M. & Lannbroek, H.J. (1996) Dynamics of nitrification and denitrification in root-oxygenated sediments and adaption of ammonia-oxidizing bacteria to low-oxygen or anoxic habitats. Applied and Environmental Microbiology, 62 (11): 4100-4107.
• Brown, K. & Brooks, K. (2002) Bushland Weeds: A Practical Guide to their Management. Environmental Weeds Action Network, Greenwood.
• Clarke, A.A., Lake, P.S. & O'Dowd, J. (2004) Ecological impacts on aquatic macroinvertebrates following upland stream invasion by a ponded pasture grass (Glyceria maxima) in southern Australia. Marine and Freshwater Research, 55 (7): 709–713.
• Department of Primary Industries, Parks, Water and Environment (2008) Glyceria, Reed Sweet Grass (Glyceria maxima - Poa aquatica [Hartm.] Holmb.) Control Guide. Department of Primary Industries, Parks, Water and Environment URL: http://www.dpiw.tas.gov.au/inter.nsf/WebPages/RPIO-4ZV7D8?open - Accessed November 2009.
• Hussey, B.M.J., Keighery, G.J., Dodd, J., Lloyd, S.G. & Cousens, R.D. (2007) Western Weeds. A guide to the weeds of Western Australia. 2nd Edition. The Plant Protection Society of Western Australia, Victoria Park.
• IUCN/SSC Invasive Species Specialist Group (ISSG) (2008) Glyceria maxima (aquatic plant, grass) Global invasive species database. IUCN/SSC Invasive Species Specialist Group (ISSG) URL: http://www.issg.org/database/species/ecology.asp?si=891&fr=1&sts=sss&lang=EN - Accessed November 2009.
• Loo, S. (2008) The spread and control of sweet reed grass (Glyceria maxima). Monash University, Victoria.
• Loo, S.E., MacNally, R., O'Dowd, D.J. & Lake, P.S. (2009) Secondary invasions: Implications of riparian restoration for in-stream invasion by an aquatic grass. Restoration Ecology, 17 (3): 378-385.
• Owen, S.J. (1996) Ecological weeds on conservation land in New Zealand: A database. Department of Conservation, Wellington, New Zealand. URL: http://www.hear.org/weedlists/other_areas/nz/nzecoweeds.htm#wocrefs - Accessed December 2007.
• Parsons, W.T. & Cuthbertson, E.G. (2001) Noxious weeds of Australia. 2nd Edition. CSIRO Publishing, Collingwood.
• Sundblad, K. & Robertson, K. (1988) Harvesting Reed Sweetgrass (Glyceria maxima, Poaceae): Effects on growth and rhizome storage of carbohydrates. Economic Botany, 42 (4): 495-502.
• USDA, ARS, National Genetic Resources Program (2009) Germplasm Resources Information Network - (GRIN). National Germplasm Resources Laboratory, Beltsville, Maryland. URL: https://npgsweb.ars-grin.gov/gringlobal/taxon/taxonomysimple.aspx - Accessed October 2009.
• Wei, A. & Chow-Fraser, P. (2006) Synergistic impact of water level fluctuation and invasion of Glyceria on Typha in a freshwater marsh of Lake Ontario. Aquatic Botany, 84: 63-69.