What is Winter Grass (Poa Annua)?

Winter grass can prove to be unsightly if you do not take action. It may also reduce the quality of your turf.

Winter grass is a common problem for Australian lawns.

This article will give you all the information you need to identify winter grass and deal with it so it doesn’t come back.

What is winter grass?

Winter grass, or Poa Annua, is an annual weed that germinates in Autumn and dies during hot periods in Summer.

Although it sometimes only lives for a few months, winter grass spreads very easily because it produces abundant quantities of seed.

Winter Grass Poa Annua 1 | Weed control

These small creamy white seeds are wind-blown, which means they can spread into your lawn from neighbouring properties.

Winter grass is a thin-blade weed that grows in clumps and is most noticeable when the lawn thins out.

How to identify winter grass

Winter grass can be identified by its seed heads and soft leaves.

Seed heads

Winter grass produces a flower branch with small creamy white triangular seed heads that come off very easy from the plant when touched.

Winter Grass Poa Annua 3 | Weed control


Winter grass has soft thin-blade leaves that are a light green colour and fold inwards.

It has soft leaves, so can be distinguished from some other weeds by bending a leaf.

The video below should help your weed grass identification:

What time of year does winter grass grow?

When soil temperatures drop to around 12 degrees Celsius in the autumn, winter grass will begin to germinate and grow.

As you enter the winter months and temperatures continue to cool, winter grass will become visible.

As it matures, Winter Grass becomes a thick, tufted, or clumping plant.

As temperatures rise in Spring or Summer (depending where in Australia you live), winter grass will go to seed.

Where in Australia does winter grass grow?

Winter grass is found throughout Australia.

In warmer climates, the seed may germinate in early autumn and grow until late spring.

Winter grass can be found year-round in colder parts of Australia.

How to get rid of winter grass

If you’re sick of winter grass and want to remove it from your yard, there are a few ways to go about it.

Manual removal

First, you can pull out the winter grass manually.

This is an effective option for small patches of the plant, but will quickly become tedious if the invasion has progressed beyond this point.

If the problem covers a larger area than this, then using herbicide would be more efficient (and less painful for your back).

Post-emergent herbicide

If you use herbicide on your lawn, make sure to get the appropriate one for winter grass in particular, as non-selective herbicides can also damage the lawn you want to protect.

A popular post-emergent is Amgrow Winter Grass Killer.

Keep in mind that with this option, the weeds may already have produced seeds, so while you may kill the existing weeds, you may have twice as many next year.

Pre-emergent herbicide

A third option is using a pre-emergent herbicide that will stop the winter grass seed from germinating in autumn.

You will need a product formulated specifically to target winter grass. Popular products include:

  • Barricade (Prodiamine)
  • Oxafert (Oxadiazon)
  • Munns Professional Winter Grass Killer (Propyzamide)

Finally, keep in mind that different herbicides are suitable for different types of lawn (e.g. Couch, Buffalo, or Kikuyu) so be sure to check that the product you are using is suitable for your specific situation.

When to apply Amgrow winter grass killer

Amgrow Winter Grass Killer is a post-emergent herbicide for killing winter grass. The active ingredient is Endothal.

Apply Amgrow Winter Grass Killer when you first see winter grass in late winter to early spring.

Be sure to spray before the grass starts to produce seeds, because new germinations will need to be re-treated.

How to prevent winter grass from growing

Prevention is the best cure, as they say.

Keeping your lawn healthy and strong will be your best defence again winter grass infestations.

A healthy, thick lawn will prevent winter grass from germinating and becoming established.

Keep your lawn well maintained by regular mowing, fertilising, and avoiding bare patches.

Aeration with a lawn aerator will also help roots grow deeper, making the lawn more densely populated with grass blades – a happier, healthier lawn.

How does winter grass spread?

Winter grass is a weed and weeds live to spread.

This means that if you have winter grass you will need to treat it to stop it from growing and spreading into your lawn.

The seed of the winter grass plant is small, lightweight, and fluffy so it can easily travel distances through wind, water or soil movement.

The seeds are designed for long-distance travel which is why this weed can be found almost everywhere.

Should you pull out winter grass?

Winter grass is an unwelcome pest and should be removed from your lawn as soon as you see it.

The best time of year to remove winter grass is when it is young, which typically occurs in late autumn or early winter.

You can use your hands or a garden fork to pluck these pesky intruders out of the soil. Wear gloves so you don’t hurt your hands and make sure to get each plant’s roots so that they won’t just regrow later on.


Does winter grass die in summer?

Winter grass will usually die back in summer, although this will depend on the specific temperatures in your region.

Photo of author

Steve Kropp

Based in Melbourne, Steve's passion is vegetable gardening, and he’s been writing about it for almost 5 years. He also loves all things DIY and is always looking for a new project. When not working on his own garden projects or blogging, Steve enjoys spending time with his family, cooking meals with produce harvested from his garden, and coaching his son’s footy team.


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