'Grass weeds' is a term used to describe weeds that are grasses (plants from the Poaceae family) or look like grasses. They're found in lawns, garden beds, verges and pastures. Grass weeds grow easily in Australia's climate and spread quickly making them difficult to control. To manage weeds in lawns and gardens, it's important to treat them quickly and regularly. Here are some of the most common grass weeds found in Australia.
Eleusine indica
Crow's Foot Grass is generally an annual (lives and dies within a year) and sometimes a short-lived perennial (lives longer than a year).
Plants can grow up to 1 m high, but when young or in a lawn situation they grow flat to the ground.
Leaves are long, thin, and green with slightly hairy edges (margins).
Flowers resemble a crow's foot and are in groups of 2-10 spikelets with one spikelet growing lower down the flower stem.
Can be found in garden beds, lawns, roadsides, near wetlands and coastal areas.
In garden beds, spot treatment with a non-selective weed killer is ideal. To control Crow's Foot Grass in a garden, carefully spot spray individual plants with a non-selective weedkiller like Yates Zero Weed Killer 490 g/L Super Concentrate. For a glyphosate-free option spray plants with Yates Zero Triple Strike Garden Weedkiller. Reapply if regrowth occurs. With non-selective weed killers be careful not to spray nearby lawns or plants as it may injure or kill them. To avoid overspray, when spraying keep the nozzle as close to the weed as possible.
To prevent Crow's Foot Grass growing in lawns, apply Munns Professional Lawn Weed Preventer in early spring. It's a specialty lawn care product and will prevent Crow's Foot Grass seed germinating for up to 6 months.
Cyperus rotundus
This perennial weed, a type of sedge, grows between 20-50 cm tall with narrow, light green linear leaves that arise from a tuft at the base of the stem.
It's tough and invasive nature can be attributed to its creeping underground stems or 'rhizomes', which aggressively creep into surrounding areas. Purple egg-shaped tubers or 'nuts' usually 1-2 cm long form on the rhizomes and are the energy store from which new shoots and rhizomes are produced.
Flowers are reddish to purple flattened spikes and appear from summer to autumn.
Seeds are ovoid, 1 mm long and can be coloured black, brown or dull green.
Nutgrass is a common weed in lawns, garden beds, parks and pastures, and favours moist and boggy soils.
There are various options to control Nutgrass in garden beds, paths and rockeries. These options are non-selective, so you will need to take care when spraying or applying near plants you don't want killed. If the infestation of Nutgrass in your area is high, multiple applications of weed killers may be required to get it under control. Once the weeds have died, dig out as many of the tubers and rhizomes as possible. Observe the area closely as this disturbance can cause new shoots to arise – if there is any regrowth, treat as soon as possible.
For the control of Nutgrass in a garden, spot-spray with Yates Zero Ultra Tough Ready-to-Use.
For the control of Nutgrass in paths, driveways, car parks and areas of bare soil where no plants are to be grown in for at least the next 12 months, apply Yates Pathweeder Concentrate - it kills existing weeds and in ideal conditions prevents new weeds germinating for up to 12 months.
To control Nutgrass in lawns, apply Munns Professional Nutgrass, Mullumbimby Couch and Broadleaf Weed Killer. It's best to apply just prior to Nutgrass flowering.
Megathyrsus maximus var. maximus
This perennial weed forms a large clump of tufted grass with short underground rhizomes.
It typically grows 1.5 m tall and wide, although some can grow to 3 m tall.
The leaves are narrow with a prominent mid-rib and pointed tips.
The inflorescences are finely branched, with small ovoid flower spikelets (3mm long) which can be green, purplish or red.
Seeds are oblong and are often purple.
Guinea Grass, also known as panic grass, is a highly invasive weed species of pastures that has spread to nature strips, vacant land sites and roadsides.
It was originally introduced as stock feed or fodder for cattle and sheep. Due to its fast-growing nature, high drought tolerance and ease of seed dispersal, it has quickly become a major threat to our biodiversity by out-competing native species.
Guinea Grass reproduces from seed, so it's best to treat early when plants are actively growing and flowering, before they have a chance to set seed. To control Guinea Grass in garden beds, carefully spot spray individual plants with a non-selective weedkiller like Yates Zero Weed Killer 490 g/L Super Concentrate. For a glyphosate-free option spray plants with Yates Zero Triple Strike Garden Weedkiller. Reapply if regrowth occurs. With non-selective weed killers be careful not to spray nearby lawns or plants as it may injure or kill them. To avoid overspray, when spraying keep the nozzle as close to the weed as possible. Once clumps have been killed, dig out with mattock or similar tool.
To control large patches of Guinea Grass in a lawn, Yates Zero weedkillers can be very carefully applied to the plants. It's important to not allow the spray to contact the surrounding lawn, as the spray may injure or kill the lawn.
Chloris gayana
Rhodes Grass, also known as Feathertop Rhodes Grass, is a large clumping perennial or annual weed that grows up to 1 m tall. It forms small clumps of bluish-green stems and leaf blades between 5-25 cm long. The stems are semi-prostrate, which means they grow close to the ground and can produce roots and stems at the nodes (stoloniferous), making it an incredibly invasive weed.
The flower heads appear during summer and autumn and are clustered on the ends of stems. They start off greenish to red-brown and as they mature, darken to brown or straw colour.
The seeds are 1.5 mm long and are slightly flattened ovoids.
Rhodes Grass is considered a major pest and is widespread along eastern parts of Australia. It can be found in crops and pastures, grasslands, roadsides, gardens and parklands.
Plants can spread into neighbouring areas via their creeping stems or stolons. Actively growing plants should be sprayed with a non-selective weedkiller, such as like Yates Zero Weed Killer 490 g/L Super Concentrate. For a glyphosate-free option spray plants with Yates Zero Triple Strike Garden Weedkiller. Reapply if regrowth occurs. With non-selective weed killers be careful not to spray nearby lawns or plants as it may injure or kill them. To avoid overspray, when spraying keep the nozzle as close to the weed as possible.
If you are spraying large areas of Rhodes Grass, you can mix in Yates Easy See Spray Dye so you can see exactly where you've sprayed
Rhodes Grass also easily spread via seeds, so seed heads must be stopped to help break the lifecycle. Apply a weedkiller when seed heads begin to form and repeat applications for any regrowth.
Lolium rigidum - Annual Ryegrass
Lolium perenne - Perennial Ryegrass
Both Annual and Perennial Ryegrass species are upright clumping grasses made up of dark green glossy leaves that are tinged purple at the base. They flourish in cool conditions and can grow 50-90 cm in height, although they are often shorter in lawn situations. In warmer climates, their growth can be restricted.
The flowering stems produce flat spikes along the tip of the stalk and appear in winter and early spring.
Seeds follow in spring to early summer and are 4-6 mm long and flat. A high number of seeds are produced per plant and are quick to germinate after a rain event, making it difficult to control.
Even though Ryegrasses are used widely used as turf/lawn, they can be considered weeds of warm season grass lawns, garden beds, and crops and pastures.
As seeds are produced in spring and summer, the best time to control is autumn and winter, prior to weed seed setting.
Unfortunately, there are no selective weedkillers that kill Ryegrass, so it is best to only spot-spray large areas of this weed with a non-selective weedkiller such as Yates Zero Weed Killer 490 g/L Super Concentrate. For a glyphosate-free option spray plants with Yates Zero Triple Strike Garden Weedkiller. Reapply if regrowth occurs. With non-selective weed killers be careful not to spray nearby lawns or plants as it may injure or kill them. To avoid overspray, when spraying keep the nozzle as close to the weed as possible.
If you don't want Ryegrass in your lawn, and spot-spraying is not practical, you will need to consider installing a new lawn.
Echinochloa crus-galli - Barnyard Grass
Echinochloa colona - Awnless Barnyard Grass
Barnyard Grass is a tufted annual grass with flat light green leaf blades that are 30 cm long. The flower spikes are green or purple and crowded along the tip of the stalk. It has a short awns or hair-like bristles (up to 50 mm) on the ends of its seeds.
Awnless Barnyard Grass is a low-growing tufted weed that grows up to 1 m tall. As its name suggests, the seeds are "awnless".
Both species are prolific seeders, producing more than 40,000 seeds per plant which can persist in the soil for up to 12 months. Seeds germinate after heavy rains in late spring and summer.
Barnyard Grasses are a common weed of lawns, garden beds, crops and pastures, drains and waterways.
In garden beds, spot treatment with a non-selective weed killer is ideal. To control Barnyard Grass in a garden, carefully spot spray individual plants with a non-selective weedkiller like Yates Zero Weed Killer 490 g/L Super Concentrate. For a glyphosate-free option spray plants with Yates Zero Triple Strike Garden Weedkiller. Reapply if regrowth occurs. With non-selective weed killers be careful not to spray nearby lawns or plants as it may injure or kill them. To avoid overspray, when spraying keep the nozzle as close to the weed as possible.
To prevent Barnyard Grass (Echinocloa crus-galli) growing in lawns, apply Munns Professional Lawn Weed Preventer in early spring. It's a specialty lawn care product and will prevent Barnyard Grass seed germinating for up to 6 months.
Bromus diandrus - Great Brome
Bromus rigidus - Rigid Brome
Bromus catharticus syn. Bromus wildenowii - Prairie Grass
The above-mentioned Brome Grasses are the most common of the Brome Grass. All are densely tufted annuals or short-lived perennials with dull hairy green stems and leaves that can grow up to 1 m.
Brome grasses all look very similar, but their flower and seed heads differ slightly in colour and shape. Clusters of purplish-brown or straw-coloured flowers appear on the ends of stalks during spring and summer, followed by small oval seeds from autumn to spring.
Brome Grasses persists so well in landscapes due to their prolific seed-bearing nature, producing an average of 1000 seeds / m2. They're also well adapted to low rainfall and because of their aggressive root systems, they can outcompete other crops and vegetation for water and nutrients. The seeds can also remain viable in the soil for up to three years.
Brome Grasses are found in crops and pastures, native vegetation, and gardens.
As Brome Grasses spread by seeds, it's important to prevent seed set and control early in the season with a suitable weedkiller. Spray when weeds are actively growing in spring and summer.
Unfortunately, there are no selective weedkillers that kill Brome Grass, so it is best to only spot-spray large areas of this weed with a non-selective weedkiller such as Yates Zero Weed Killer 490 g/L Super Concentrate. For a glyphosate-free option spray plants with Yates Zero Triple Strike Garden Weedkiller. Reapply if regrowth occurs. With non-selective weed killers be careful not to spray nearby lawns or plants as it may injure or kill them. To avoid overspray, when spraying keep the nozzle as close to the weed as possible.
