Parramatta Grass, along with most of the weedy Sporobolus grass family, has become a huge and increasing problem for landholders. This article discusses a couple of control methods and is not intended to be a definitive article on this grass family.

We own a 32 acre property in Peachester on the Sunshine Coast. We bought our property 12 years ago and started an extensive program of weed removal and replanting with endemic species. Our property could have been mistaken for a Camphor Laurel farm and their removal is ongoing, along with all the other usual suspects, mainly Small and Large-leaved Privet, Lantana, Yellowberry, Ochna, Castor Oil etc.

We also started improving the pastures. Two years later we noticed a one metre high tussocking grass with large black seed heads starting to appear in a few paddocks. It was not noticed until we completely rested one paddock, allowing this tussock grass to grow to its full height. Before spelling they were eaten off to low levels and were not obvious.

After investigation we confirmed that these large tussock grasses were Parramatta Grass (Sporobolus africanus), one of the weedy Sporobolus grasses (WSG) family. This WSG family is better known for the infamous Giant Rat’s Tail Grass (Sporobolus pyramidalis) and Giant Parramatta Grass (Sporobolus fertilis).

An image of GRT grass
Correctly identifying weedy Sporobolus grasses can be difficult. Identification often requires examination of the seed head by microscope, best done by the Queensland Herbarium. Above is a Giant Rat’s Tail Grass, right is a suspected Giant Parramatta Grass. Photos by Bruce Lord.

Once identified we started to notice Parramatta Grass in patches in all the cattle grazing paddocks with increasingproliferation over the next year. All weedy Sporobolus grasses are spread rapidly by stock, vehicle movement, wind and flood water. These grasses grow rapidly, are frost and drought resistant and carry approximately 80,000 seeds per plant. They have the ability to infest paddocks and ultimately overtake other more productive grasses and render properties virtually useless for stock. They are one of the biggest developing flora problems facing landholders in eastern Australia.

Thankfully there has been the development and availability of a WSG specific selective herbicide called fluproponate, which is marketed as Taskforce, Scuffle and other commercial names. Fluproponate will also work as a pre-emergent on the remaining soil seed bank as well as the parent plant. This chemical is successful but takes between 3 and 15 months to kill WSGs depending on weather conditions. It is washed into the soil by light rain and is subsequently taken up by the plants surface roots. It is most effective during summer months as the plant takes up the chemical more quickly. However, it may be washed out of the soil before becoming effective if application is followed by heavy rain, as is likely in the summer months.

Fluproponate is applied by spray and can be boom or spot sprayed. However it requires careful application. It must be applied at the precise rate as described by the manufacturer which requires calibration of boom sprays and this is seen as somewhat difficult to most landholders. If applied too heavily it may affect the other desirable grasses, too lightly and it is ineffective.

A new product called GP Pellets is now available. These pellets are a granular form
of fluproponate and have a fast release outer coating and a slower release inner. It can be applied by hand, mixed with fertilizer and spread accordingly but is very difficult to apply accurately with these methods. A hand-held spreader, such as the Scotts brand, is a much more accurate method of application but is not practical for larger areas.

The GP Pellet manufacturer offers a service using distribution by helicopter. This method applies the pellets very accurately using calibrated pods on the helicopter and GPS grid navigation. It applies the pellets very accurately in open fields and can apply them successfully through wooded areas and rough country which are usually not sprayed with boom sprays. This method may sound initially very expensive but when costed out the cost is almost the same as buying the pellets for the area. It has the advantage over other methods of very accurate distribution and huge time saving.

We treated our property using GP Pellets distributed by a helicopter, as well as our neighbours on either side (this is ideal), in March 2016. Shortly after treatment we had 5-10 mm showers every week or two and an unseasonally warm autumn, which resulted in a very active extended growing season. Three months after application there has been a very noticeable change in Parramatta Grass: A new control method weed profile Weedy Sporobolus grasses have the ability to seriously degrade properties and doing nothing is not an option. the Parramatta Grass infestation with most Parramatta Grass turning brown, dying or dead.

An image of GRT grass
Giant Rat’s Tail Grass can quickly spread across paddocks turning fertile pastures into unproductive land.

The base of dying or dead Parramatta Grass tussocks are now being overgrown with grasses and legumes, demonstrating that the fluproponate has only affected the Parramatta Grass. The manufacturer recommends a second application two years later to ensure near total eradication.

Weedy Sporobolus grasses have the ability to seriously degrade properties and doing nothing is not an option. They are considered Restricted Invasive Plants under the Queensland Biosecurity Act 2014 (formerly Class 2 Declared Pests), which means that the landholder must take reasonable and practical steps to keep their land free of this pest, and that plants must not be given away, sold or released into the environment.

Weedy Sporobolus grasses need to be addressed and GP Pellets along with their distribution by helicopter gives landholders a viable, practical and economical tool to control this major problem.

If you have WSGs on your property, we suggest that you refer to all resources available including local Land for Wildlife Officers, the Queensland State Government, Department of Agriculture and Fisheries and other landholders.

Article by Brian & Christine Stuart-Nairne
Land for Wildlife members
Peachester, Sunshine Coast

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22 responses on “Parramatta Grass: A new control method

  1. Excellent article and just exactly what we need.
    Who do I contact regarding this application method and find out what the application cost for our property will be.
    We are south of Canungra and have 50 acres of which 40 will need treating.
    Approximately two thirds is fairly open paddock with the remainder fairly mature gum forest.
    The infestation is quite minimal in some areas but is spreading quite rapidly in others.

  2. Hi Brian & Christine. Our property is at Dayboro and the helicopter application would be great. Can you recommend a helicopter service. Regards. Leigh.

  3. I am not a farmer just a 6 acre landowner with a little Parramatta grass on my land
    Can I use flysophate to kill it?
    If not, what is the amount of fluproponste in a 10 lt backpack ?
    Thank you

    1. Thanks for a good article. It also can work for the Nassella species as well such as Serrated Tussock/Chilean Needle Grass (in the south). Soil types are also important in terms of fluproponate application as lighter sandy soils will need a lighter application rate as heavier soils have a more buffering effect of the chemical. So be careful of soil types and rates! Also withholding period for reentry for livestock can be long.

    2. Depends on your soil types…….lighter soils usually require lower rate…..less buffering effect. Experiment with different rates/ how much rainfall you got after application/soil moisture levels and record for each rate. That’s the safest thing to do. In the meantime as a stop gap to stop further spread – cut off seed heads, put in bag and either bury deep or burn the heads (not the bag). Also there is some experimentation with spraying molasses on the plants to make them more palatable to livestock??

    3. Hi Sue, I read that 200mls to 100 litres of water
      since the bushfires with the summer rain it is everywhere on our farm in Kangaroo Valley, started boom spraying last week-Feb 2021

    4. Hi again Sue- downloaded this from suppliers web site
      Rates: (General Only)

      Spot Spraying: 75mL – 500mL per 100L Water
      Boom Application: 2L – 22L per Ha
      Aerial Application: 500mL – 2L per Ha
      Kangaroo Valley

  4. An interesting article. However, I see there is no mention of withholding periods for livestock. My understanding is that there is a very long withhold period of 4months plus when using this chemical. Given this time frame one would have to build this factor into the available grazing biomass.

  5. Hi, thanks for an informative post.
    I bought a small acreage (5.5ac) last Nov, which was mown within an inch of it’s life. I’m originally Victorian and while I had heard of Parramatta/Rats tail I hadn’t actually seen it. I asked the RE agent if there was any present, he responded ‘Maybe a bit’…I went to Melbourne to organise my mother’s unexpected funeral just prior to Christmas and came back to a magnificent crop, I beheaded the seeds and sprayed the plants, day in and out, when it was hard to find I mowed, needless to say it’s come back, but I’m on top of the new crop (sometimes 5 hours of digging them out by the root per day.) My neighbours all think I’m insane, they make no attempt to control it. One is riding his motor bike around in it as I type this. The council occasionally sprays the road verge. They had the worst offender (350ac neighbouring cattle property) mow me a 10 mt strip on his side of the fence (once)..
    I’m not certain I can keep up the fight but I’ll give it my best shot. However, I didn’t buy a ‘lifestyle’ property to listen to the perpetual roar of motor bikes and weeding non stop.. The Queensland government needs to give subsidies to land owners who do the right thing.

  6. We have a problem on a golf course in eastern Victoria. Our concerns are killing the couch and other grasses whilst trying to eradicate the Parramatta Grass. If applied correctly will fluproponate only kill the Parramatta Grass? Our Parramatta Grass is much smaller than what is described above but looks identical and we have been told it is Parramatta Grass.

    1. Rob, did you reply on this. our golf course is in the Northern Rivers and the grass would as tall as shown but the mowers keep them down. It would be good to eradicate the grass and it wouldn’t matter how long it took.

  7. This invasive weed is of no nutritial value and a bigger problem than blackberries or thistles .ignore it at your own peril

  8. Hi since the 2018 drought and then 2019/ 2020 fires and now 2021 has been a wonderful year for rain on Mid North Coast.
    The parramatta grass and Giant parramatta grass has gone wild .
    I dehead bucket loads and would like to use flupropanate granular as against spraying but do not want to lose my kikuyu . Can I just broadcast it where the P grass is as it does not like the competition of heavier grasses out of a bucket as apposed to a broadcaster
    Thanks Gary Ellis

  9. Interesting, but at the end of the day if you aren’t treating the cause (overgrazing) you probably wont be successful long term. The issue with weeds is hardly ever the amount of seeds out there (seeds are everywhere and long lived in soil) its the conditions that allow those seeds to grow. You think you paddock isnt full of every weed seed known to humans? It is. Its the grass that keeps it suppressed most of the time. Im yet to win the battle, but believe use of the Soil trooper fungus combined with letting grass in paddocks grow very long, then crash graze, then grow long again, will see parramatta grass not take over. Think about the conditions that parramatta grass like. Compacted soil, closely grazed pasture. Make your farm the opposite of that. The thing has a low crown, it hates having thick mulch applied to its top and being shaded out by other scrambling type grass like kikuyu or paspalum. If your other grass wont grow tall and smother it then you can see where the problem is, your soil is overgrazed and tired. When you are dropping poisons from helicopters you know you are in trouble.

    1. Your comments are interesting Fred, but every farm is different. You cannot apply your experience and organic farming beliefs to a “blanket” solution for Parramatta Grass and Giant Parramatta Grass.

      On a former dairy farm in Clarence Valley we have had some success using Flupropanate at 1.5L per Ha on kikuyu pasture. 2.0L per Ha has caused more damage to non-target grass species.

      Despite our best efforts to reduce compaction, improve soil health and pasture quality in our cell grazing operation for breeding beef cattle, we find Flupropanate an essential part of our management mix every five years or so.

  10. I think it is worth noting that the liquid formulations of fluproponate products are just as effective, can also be applied by helicopter at the correct rate and are cheaper than the granular product. They have been spraying liquid fluproponate for other weedy grasses for decades.

    it is also worth noting that any chemical that is applied through a boom spray needs to be done with a calibrated boom so if people are spraying other chemicals or solutions with a calbrated boom spray there is absolutely nothing stopping them spraying fluproponate with a boom.

    As to the grasses that fluproponate will kill there is information on the label that can be found online and the serrated tussock and giant parramatta grass National best Practice manuals. All available online.

  11. Great reading. I have 10 acres in Palmwoods, and When the army worm came through in I think summer 2019 the WSG really took off. I’m now going to spot spray, using dye so I can see where I’ve been. Wish me luck…

  12. Delaneys Creek 16 h’s. Back boundary slope covered in WSG. Restisted using chemicals broadscale so fenced it off and left it. It is starting to choke itself out and other grasses are starting to take over.

    The rest of the property has small out breaks that I spot spray the roots using a cheap Bunnings 2L pressure spray. I take a container of water on the quad and mix 2L at a time using a small syringe to measure with. I find it a better way than mixing 25L in a quad mounted drum, only to not use half of it for a year. I keep a 2L bottle ready any time I see a few. About the do it in one paddock again as soon as the rain thins out.

    Overgrazing is the biggest spreader of this weed. Neighbors have a bordering paddock completely covered in it, Interestingly the one they have donkeys in never has a chance to make seed.

  13. People should bare in mind Fluproponate will kill most grass species if used at high enough rate. It is not selective to Parramatta grass. For boom spraying (or helicopter) just try and work out if the grass you are trying to keep is less susceptible than what your trying to kill. For spot spraying the sensitivity is less critical.

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