Rainbow over Camel’s Hump Conservation reserve.

Giant Parramatta Grass (Sporobolus fertilis)

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Giant Parramatta Grass

Giant Parramatta Grass is an invasive, dense, perennial, tussock grass. It thrives in coastal areas and is widespread in paddocks and on roadsides of the Mid Coast of NSW.

Giant Parramatta Grass has many negative impacts, such as; outcompeting pasture grasses, reducing productivity and the value of grazing land, competing with native plants, and increasing fuel loads.

What does it look like?

Giant Parramatta grass is a dense, perennial, tussock grass. It usually grows up to 2 m tall.

Leaves are:

  • long and thin with pointed tips
  • up to 110 cm long and 5 mm wide
  • flat, folded or rolled inwards
  • ribbed and hairless
  • sometimes drooping

The leaf sheath is ribbed and hairless and the ligule at the junction of the leaf and leaf sheath is a fringe of small hairs.

 Flowerheads are:

  • dense with many branches held close to the main stems (some mature branches droop away from the central stalk)
  • 25–45 cm long and 1–2 cm wide
  • made up of dark green spikelets1.5-2 mm long
  • present from spring to autumn

Seeds are:

  • 0.8–1.2 mm long and 0.5–0.75 mm wide
  • yellowish-brown or reddish-brown when mature
  • sticky when mature.

Stems are:

  • arranged like a fan
  • usually not branched
  • 2-5 mm in diameter
  • hairless
  • slightly wiry

Similar looking plants

It is difficult to identify Sporobolus grasses prior to seed set. Giant Parramatta grass looks like other weedy Sporobolus grasses including:

  • Parramatta grass (Sporobolus africanus), which is usually shorter (<1 m tall) and has smaller seed heads (up to 18 cm).
  • Giant rat’s tail grass (Sporobolus pyramidalis) which is very similar but as the seed head matures its branches move apart to form a pyramid.

Giant Parramatta grass also looks similar to some native Sporobolus grasses including:

  • slender rats-tail grass (Sporobolus creber)
  • slender rats-tail grass (Sporobolus elongatus)

Both these species are smaller (usually less than 100 cm tall) and have less dense seedheads.

Video Resources

Giant Parramatta Grass - Identification & Characteristics


Giant Parramatta Grass - Control & Management Methods


Giant Parramatta Grass - Controls, Management & Issues - A landholder perspective


Giant Parramatta Grass - The neighbour's property has GPG, what should I do? A council perspective.

References

NSW DPI WeedWise – Giant Parramatta Grass – https://weeds.dpi.nsw.gov.au/Weeds/GiantParramattaGrass

Videos produced by Hunter Local Land Services

 

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