Winter Dormancy of Warm Season Grasses

Weeds in Perth lawns are generally more prevalent in winter due to the grass varieties going dormant. A dormant grass does not use many nutrients or grow a lot, leaving food and space available for the weeds. Basically, a weed will grow in a spot which has a weak grass sward.

This is why breeding grass varieties which have lower winter dormancy is an important factor in turf breeding. New age turf varieties such as DNA Certified Sir Walter and TifTuf have very good winter dormancy properties, so they are better able to fight of weeds.

How to Fight Weeds

Fighting off winter weeds starts in summer. Making sure you have full grass coverage and a healthy grass sward will eliminate bare patches. To do this means you need an effective watering system and fertilising program

Another important weapon in fighting winter weeds is making sure you feed your lawn in May. This feed is the most important of the year for stopping your lawn going to sleep and becoming dormant.

Most weeds in Perth lawns can be grouped into the following categories:

Winter Weeds (Broadleaf weeds)

These weeds include clovers, flatweeds and dandelions. Basically, anything that looks like a plant growing in your lawn. There are two main types of active chemicals for the home gardener; Bromoxynil for Buffalo varieties and Dicamba for couch and kikuyu varieties.

Type of weed – Bindii / Onehunga / Jojo

Product – Kleen Lawn, Bow and Arrow, Double Time

Grass Type – Couch and Kikuyu

Product – Buffalo Master, Bow and Arrow and Oxyfert

Grass Type – Buffalo, Velveteen, Zoysia, QLD Blue

Bow & Arrow


Bow & Arrow Herbicide is the standard for broadleaf weed control in the Australian turf industry providing outstanding control of broadleaf weeds in turf.

Type of weed – Clover

Product – Kleen Lawn, Bow and Arrow, Double Time

Grass Type – Couch and Kikuyu

Product – Buffalo Master, Bow and Arrow and Oxyfert

Grass Type – Buffalo, Velveteen, Zoysia, QLD Blue

Bin-Die Weedkiller 100ml


Bin-Die weedkiller has been formulated especially for use on buffalo lawns (except ST Varieties of buffalo). Bin-Die can also be used on couch, bent, kikuyu, paspalum.

Type of weed – Flatweed / Cats ear

Product – Kleen Lawn, Bow and Arrow, Double Time

Grass Type – Couch and Kikuyu

Product – Buffalo Master, Bow and Arrow and Oxyfert

Grass Type – Buffalo, Velveteen, Zoysia, QLD Blue

OxaFert Pre – Emergent Weedkiller


OxaFert weedkiller is a pre-emergent herbicide and fertiliser that targets weed seeds before they take hold. Targeted weeds are Broad Leaf Weeds such as bindii and flatweed, Wintergrass, Summergrass, Creeping Oxalis and Crowsfoot.

Other Weed Types

Guildford Grass (Onion Grass)

Guildford Grass (onion grass) is very shiny and come up in sandy soil areas that have a weak grass sward during winter. They are very difficult to cut with a cylinder type mower and grow from a bulb.

Type of Weed – Guildford Grass

Product – Ken Met

Grass Types – All Lawn Types

Nutgrass / Sedge

Nutgrass, Sedge and Mullimbimby Couch has a rhizomatous root system and a very shiny leaf that resists chemical penetration. For this reason, it is recommended that you use a good quality wetting agent (surfactant) mixed with your chemical

Type of weed – Nutgrass

Product – Sempra

Grass Type – All lawn types

Product – Amgrow Paspalum, Nutgrass & Clover Killer (DSMA)

Grass Type – ONLY Couch


Winter grass is a tiller type grass that has its own root system like rye and fescue. It is difficult to control as it has built up resistance to most chemicals. The best control is a preemergent application around May. Alternate your chemicals where possible to minimise resistance building.

Type of weed – Wintergrass (Poa Annua)

Product – David Grays Winter Grass Killer, Amgrow Winter Grass Killer, Oxyfert and Embargo

Grass Type – All lawn types

Out of stock

Halo-Force 750 WG


Sempra is used for the selective post-emergence control of nutgrass and Mullumbimby couch in lawn.

Creeping Oxalis

Creeping Oxalis is a small weed that resembles clover with bright yellow flowers. It moves very quickly and is tricky to pull out by hand as the crowns break of leaving the roots in the soil.

Product – Ken Met

Grass Types – All Lawn Types

Product – Double Time and Casper

Grass Type – Couch and Kikuyu

Product – Buffalo Master and Oxyfert

Grass Type – Buffalo, Velveteen, Zoysia, QLD Blue

Casper Herbicide


Casper is a selective post-emergent herbicide specifically formulated for use on turf. Casper provides highly effective control of broad leaf weeds.

Wetting Agents

Many weedkillers are more effective when mixed with a wetting agent. The wetting agent helps the herbicide to penetrate the leaf and get  into the soil.