Sedge Weeds - Lawn Solutions Australia

Sedge Weeds

Sedge weeds are some of the worst weeds when it comes to their ability to infiltrate your lawn.

They are highly invasive, very difficult to get rid of and only some specific chemicals, that are not always easily available, target them without harming your lawn.

Sedges are part of the Cyperus genus which includes about 700 types of sedge. Sedges have triangular cross-sections and spirally arranged leaves in 3 vertical rows along the stem. A common factor in areas where these weeds tend to occur is poor soil.

For this article we are going to focus on two in particular that are commonly found in Australian lawns, Nutgrass and Mullumbimby Couch.


Botanical name: Cyperus Esculentus


  • Nutgrass gets its name from the nut-like tubers found on the roots (rhizomes) of the plant.
  • Nutgrass is identifiable as it is usually a lighter green than the rest of your lawn and tends to grow taller.
  • Nutgrass has 3 blades that shoot up from the stem and has a triangular stem rather than a circular stem like most grasses.

nut grass


Mullumbimby Couch

Botanical name: Cyperus brevifolius


  • A perennial mat-forming, grass like sedge up to 15cm high with dark green, glossy, strap-like leaves.
  • Possesses tough long, rhizomes which are red to purple in colour.
  • Grows best in areas of excessive soil moisture and humidity and can be difficult to control due to a strong network of rhizomes from which individual plants can regenerate.

mullumbimby couch


Nutgrass and Mullumbimby Couch are incredibly difficult to eradicate so it is best you act quickly before they spread and become almost impossible to remove.

You can remove them by digging them out with a small spade. But you have to be extremely diligent with this to ensure there are no roots or bulbs left in the soil as they will reappear if left behind.

Sedge Post-Emergent Herbicides

If there is a large amount of Nutgrass or Mullumbimby Couch in your lawn, you will need to treat it with a selective herbicide such as Amgrow Sedgehammer or Sempra.

  • Sedgehammer can be safely used on lawn varieties including bent grass, buffalo, couch, kikuyu, perennial ryegrass, QLD Blue couch and Tall fescue.
  • Sedgehammer is a 750g/kg water dispersible dry flowable formulation of Halosulfuron methyl.

Another herbicide option is Paspalum, Nutgrass and Clover Selective Weed Killer, but you can only use it to spot spray buffalo and kikuyu turf varieties as it will harm your lawn as well. It is safe to cover spray on Couch (excluding QLD Blue Couch), Bent and Fescue turf varieties.

If you don’t treat these weeds, they will continue to multiply and infest your whole lawn, so it’s definitely worth doing in order to save your lawn from continued infestation.

Remember to always follow the manufacturer’s instructions on the pack when using herbicides. These chemicals are generally on the expensive side, but you only need a very small quantity to treat the affected area. Be aware that repeated applications may also be required.

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