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
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
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
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
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
Wintergrass
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
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
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.