Winter Grass Control in Your Lawn

Winter Grass (Poa annua) is a common weed of lawns across most of Australia. It is easily noticed in lawns due to its tufted growth habit and lime-green coloured leaves which stand out in most grass lawns. Leaves are flat and smooth with boat-shaped tips.

Winter Grass seeds are small and creamy white with seeds growing along a branched spike. It is a prolific seed producer and with so many seeds produced there is naturally subtle variations in each plant. This has allowed Winter Grass to adapt to a huge range of conditions, but this can also make it difficult to control.

Despite being called Winter Grass, in cool areas of Australia it can still grow throughout the year where soil temperatures are around 12 degrees Celsius. Across most of Australia it is usually found growing in autumn as the soil cools, then again in spring as the soil warms up. Mature Winter Grass plants generally set seed in late spring due to warmer weather. However, due to variation, some plants can set seed year-round.

To stop Winter Grass seeds from successfully germinating, and kill young Winter Grass seedlings, spray the entire lawn in early autumn with Munns Professional Winter Grass Killer. It contains propyzamide, which is both a pre-emergent (prevents) and post-emergent (kills) herbicide. It works by binding with the soil, and as Winter Grass seeds germinate, the new roots take up the herbicide then die. 

Apply in early autumn to prevent Winter Grass seedlings developing, or during autumn and winter to control young Winter Grass seedlings. Please be aware that this product does not kill semi-mature or mature Winter Grass plants, and see Best Treatment for Mature Winter Grass.

Munns Professional Winter Grass Killer is safe for use on Kikuyu, Buffalo, Couch and *Queensland Blue Couch. Please be sure to read all label instructions prior to every use.

*Queensland Blue Couch is less tolerant to the herbicide and applications are best split into two applications, four weeks apart.

If you missed the ideal spraying time for Munns Professional Winter Grass Killer in early autumn, and  now there are patches of mature Winter Grass growing in your lawn, spot spray with Yates Zero Triple Strike Garden Weedkiller or Yates Zero Weedkiller 490 Super Concentrate. These sprays are non-selective, so only spray onto the weeds and avoid spraying the lawn as it can be damaged by over-spray.

One of the best ways to combat Winter Grass is to grow a thick and dense lawn where there is less water, light and nutrients available for seeds to germinate and grow. Feeding your lawn 3-4 times per year with a specialised lawn fertiliser like Munns Professional Golf Course Green will help grow a thick and dense lawn. 

Shaded areas of lawn can be thin and patchy, and together with moist soil it creates the perfect environment and opportunity for Winter Grass to thrive. If nearby shrubs or trees are creating shady conditions over the lawn, try pruning off some branches to let in more light and promote thicker lawn growth.