Glyceria maxima (Hartm.) Holmb. Water Meadowgrass
Bot.Not. 72:97 (1919)

Conservation Code: Not threatened
Naturalised Status: Alien to Western Australia
Name Status: Current

Brief Description
Grazyna Paczkowska, Thursday 18 November 1993

Rhizomatous, aquatic perennial, grass-like or herb, 0.3-1 m high. Fl. green, Dec or Jan to Feb. Gritty sandy clay. Creeks, pools.


Beard’s Provinces: South-West Province.

IBRA Regions: Jarrah Forest, Swan Coastal Plain.

IBRA Subregions: Dandaragan Plateau, Southern Jarrah Forest.

Local Government Areas (LGAs): Donnybrook-Balingup, Gingin.

Management Notes (for the Swan NRM Region)
Kate Brown and Karen Bettink, Monday 26 August 2019

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

Calendar Type Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Comments
Active Growth Y Y Y Y Y     O Y Y Y Y  
Germination               Y Y Y      
Flowering Y Y Y             Y Y Y  
Fruiting Y Y Y Y Y                
Optimum Treatment Y Y Y Y Y             Y  

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



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Project information and acknowledgements