The number one rule of lawn weed control: read the label for your grass type. Many broadleaf herbicides that are fine on couch and kikuyu will damage or kill buffalo. "Buffalo-safe" is printed on the front of the products that are, and if it is not, assume it is not. With that out of the way, here are the weeds we deal with most across Ipswich lawns and what works on each.
Bindi (jo-jo, bindii)
Identify: a low, ferny, carrot-leaf rosette through winter that produces the prickly seed heads bare feet find in spring. Timing is everything: treat in late autumn or winter (June to August), before the prickles form. Once you can feel them it is too late for this year. Treat with: a bindi and clover herbicide labelled for your grass type, or hand-pull small infestations. A thick lawn mowed at the right height stops bindi getting established in the first place.
Nut grass (nutgrass, Cyperus)
Identify: a glossy, upright, lime-green sedge with a triangular stem that grows faster than the lawn and pops up a day after mowing. Why it is hard: it spreads by underground "nuts". Pulling it leaves the nuts behind and makes more. Treat with: a selective nut grass herbicide (halosulfuron-based products are the standard and are safe on most lawns, including buffalo). Expect two or three applications across a season. Never rotary hoe it; you just plant the nuts everywhere.
Winter grass (Poa annua)
Identify: bright, soft, tufty grass with white seed heads that appears in May and dies off in the heat, leaving bare patches. Treat with: a pre-emergent in autumn (April) to stop it germinating, or a selective winter grass herbicide once it is up. Mowing before it seeds limits next year's crop.
Clover, creeping oxalis and other broadleaf weeds
Identify: clover has three round leaflets and white flowers; oxalis looks similar with heart-shaped leaflets and yellow flowers; cudweed, plantain, capeweed and dandelion are the other usual suspects. Treat with: a selective broadleaf herbicide (bromoxipil/MCPA based products are the common buffalo-safe option). Spot spray rather than blanket spray if there are only a few. Clover is also a sign of low nitrogen, so a feed helps the grass out-compete it.
Crowsfoot, summer grass and other grassy weeds
Identify: coarse, pale, flat-growing grasses that appear in summer, often in thin or compacted areas. Treat with: these are the hardest, because most products that kill them also kill the lawn. A pre-emergent in early spring stops them germinating. Established plants are best hand-pulled, and the bare area repaired so the lawn fills in.
Getting the application right
- Spray on a still, dry morning with no rain forecast for 24 hours and no mowing for two days either side.
- Use the label rate. More is not better and can burn the lawn.
- Do not spray a drought-stressed lawn or in heat above 30°C.
- Wear gloves, long sleeves and eye protection, and keep kids and pets off until dry.
- Most lawn herbicides are registered for licensed use at commercial rates. For large areas or stubborn weeds a ChemCert-accredited operator can use products and rates that are not available over the counter.
The long game: a thick lawn
Weeds get in where the grass is thin. The cheapest weed control is a lawn mowed at the right height on a regular schedule, fed in spring and autumn, and watered deeply rather than daily. We see it on the route every week: the lawns on a schedule have far fewer weeds than the ones mowed every six weeks.
Frequently asked questions
What kills weeds but not buffalo grass?
Products labelled buffalo-safe, usually based on bromoxynil and MCPA for broadleaf weeds, or halosulfuron for nut grass. Always check the label for your grass type before spraying.
When should I treat bindis in Queensland?
In winter (June to August), while the plant is a soft rosette and before the prickles form in spring. Treating in spring is too late for that season.
How do I get rid of nut grass permanently?
Use a selective nut grass herbicide two or three times over a growing season to exhaust the underground nuts. Do not dig or pull it, which spreads it.
Does vinegar or salt kill lawn weeds?
They kill whatever they touch, including the grass, and salt damages the soil. They are not a selective option for lawns.
