There are hundreds of sedges in the genus Cyperus, which is found in both tropical and warm temperate environments across the world.
Some Sedge Grass is grown as ornamentals or pot plants, while other species with edible tubers are used for food and as a spice.
Australian types include Umbrella Sedge, Flat Sedge, Nut Grass and Mullumbimby Couch and despite their common names, Sedges are not grasses.
Sedge Grass can be annual or perennial and grows in shallow still or slow-moving water, as well as poorly drained areas and wet spots in your lawn.
They can spread by seed or rhizomes and are often brought into gardens by water, animals, mowers, or in contaminated soil.
Some Sedges might look like grass in your lawn when the plants are small, but they are distinguishable by their stiff, narrow leaf blades, triangular stems and prolific seed heads.
Sedge Grass can reproduce by seed, from rhizomes, or both.
The best way to identify which species is in your lawn is from the seed head, but the best time to remove Sedge Grass is when plants are small and haven’t had time to produce seed.
Umbrella Sedge (Cyperus alternifolius) is also known as Umbrella Palm and Umbrella Papyrus a long-lived reed-like plant with upright stems which usually grows 45-120cm tall.
Often used in ponds and water features, Umbrella Sedge has escaped and become a common weed of waterways and wetlands across Australia.
Umbrella Sedge reproduces mainly by seed but can spread from its short rhizomes to form large clumps.
Flat Sedge (Cyperus eragrostis) is also known as Tall Nut Grass, Tall Flat Sedge and Umbrella Grass.
It grows from rhizomes and has erect stems up to 90cm tall, with long, thin, pointed leaves radiating from the top.
Flat Sedge is regarded as an environmental weed in New South Wales, Victoria and Western Australia.
Nut Grass (Cyperus rotundus) has a very narrow leaf and is easily distinguishable from most turf varieties.
It’s an annoying fast-spreading long-lived perennial weed that grows from underground tubers.
There’s more information about how to take control of Nut Grass here.
Mullumbimby Couch (Cyperus brevifolius) is also known as Short-leaf Flat Sedge and Perennial Greenhead Sedge.
It is regarded as an environmental weed in parts of Western Australia, Queensland, New South Wales and Victoria.
Plants produce reddish-purple rhizomes which send up smooth, hairless three-sided stems and flower spikes that produce pale green seed heads all year round.
Mullumbimby Couch reproduces from both seed and the creeping underground runners.
There’s more information about how to take control of Mullumbimby Couch here.
Sedge Grass can be difficult to eradicate because it produces a large number of seeds and has an extensive system of underground rhizomes and tubers.
The main options for controlling Sedge Grass are mechanical and chemical methods and they are more likely to succeed if undertaken when plants are actively growing, not stressed and haven’t seeded.
Small individual Sedge Grass plants with less than five leaves won’t have grown tubers and can easily be removed by hand.
Larger Sedge Grasses can be dug up with a sharp spade, taking care to leave a generous margin around and under the roots, as well as making sure you pick up all of the runners and any bulbs that might be left behind.
Slashing and mowing can be helpful in bigger areas, but make sure the Sedge Grass is dry. If it’s wet, the seeds can stick to you and your equipment which can lead to further spread.
Avoid cultivating Sedge Grass – chopping it up will also spread it.
Applied correctly, glyphosate can be effective on Sedge Grass, but as a non-selective herbicide it will poison everything it touches, including the surrounding lawn.
Products containing the active ingredient halosulfuron-methyl can be safely sprayed on many turf varieties to kill Sedge Grass, while others should only be used for spot application. This includes products containing MCPA that are marked on the label as being suitable for Paspalum, Nut Grass and Clover.
Depending on the maturity of the Sedge Grass plants and how large an area is affected, it may be necessary for you to spray more than once.
Always read the safety directions and instructions on the product label before use.
Indigo Halo-Force 750WG 25gm is a dry flowable granule herbicide. Grasses that Indigo Halo-Force 750WG can be applied to are Kikuyu, Couch and Buffalo. Always read the safety directions and instructions on the product label before use.
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TUFFWEED Liquid Glyphosate 1L super concentrate is a non-selective herbicide. Before use always check to see if your lawn variety is suitable for the use of TUFFWEED Liquid Glyphosate 1L. Always read the safety directions and instructions on the product label before use.
SHOP NOWA program of regular fertiliser application and mowing that ensures you have a strong, healthy lawn provides the best defence against infestation by weeds such as Sedge Grass.
Learn what kind of lawn you have and take care of it properly using the right kind of fertiliser, maintaining the optimum soil pH and mowing your lawn to the recommended height.
Other preventative measures of Sedge Grass include fixing any drainage or irrigation issues and stopping water from collecting in hollows in your lawn.
Top-dressing can get rid of small dips, but in larger poorly drained areas, it might be necessary to remove a section of lawn. You can put down a mixture of compost, sand, or other amendments to increase the porosity of the upper layers of soil and then re-lay your lawn on top.
Another way to stop Sedge Grass in its tracks is by laying geofabric under new garden beds to minimise the risk of it spreading from seeds or tubers in soil that’s brought in.
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