Controlling Parramatta Grass

Parramatta grass is one of the most evasive and difficult weeds to control on Australian and to a lesser extent on South African golf courses. Native to Africa, there are three main species of parramatta grass: Giant Parramatta grass (Sporobolus fertilis formerly S. indicus var major), a smaller species of Parramatta grass (S. africanus), and Giant Rats Tail grass (S. pyramidalis).

Parramatta grass is a warm season perennial weed (C4) that is tolerant to high light and temperatures. It is more efficient in the use of water than couchgrass or kikuyugrass giving it a competitive advantage in semi-arid environments. During winter, Parramatta grass growth slows and its metabolic rate is reduced, which is one reason herbicidal control lacks consistency.

Parramatta grass germinates in spring and rapidly develops producing flowering stems during mid-summer. It is a profuse seed producer able to produce 300 seeds/head. Seed banks (seed in soil) have been reported as high as 600-4000 seeds/m2.

Suggestions and Ideas for Control:

Light infestation: If Parramatta grass is just beginning to appear, spot spraying with glyphosate is one possibility. In addition, you may want to dig up the clumps or patches. If the turf that is present is kikuyugrass, add sprigs to the spots. Kikuyugrass sprigs are very competitive against germinating Parramatta grass seeds. If seed stalks are present when cutting, collect the clippings and dispose off site. This may help reduce seed dispersal.

Heavy infestation: If digging up patches of Parramatta grass, or spot spraying is impractical, control becomes more difficult. One potential method would be to look into a wick wiping devise to apply glyphosate. The Australian Pesticide and Veterinary Medicine Authority (APVMA) has issued a permit (PER4697) for the application of glyphosate by wick wiper on giant Parramatta grass.

If a wick wiper method is not practical or suitable, experiment with making your own application unit. One suggestion would be to take a short pole or pipe made from something that does not absorb a herbicide (ex. polyvinyl chloride), rap a portion of it with a cotton cloth and dip with appropriate glyphosate solution, and brush it across the parramatta grass (especially effective if the weed is growing taller than the desired turf). Multiple applications will be needed, with multi-season applications.