How to Get Rid of Winter Grass

Written By:
Scott Carroll
Published On:
April 25, 2023
What does winter grass look like

During winter, low-growing turf grass, known as poa annua, can pose a severe problem for homeowners if left unmonitored. Winter grass (poa annua) is a widespread weed that may quickly take over a lawn, especially in cooler months, causing significant damage to your backyard.

Fortunately, we are here to provide some easy methods for removing winter grass, both pre and post-emergent. Let’s dive in!

What is winter grass?

Winter grass is a common annual weed that appears in lawns during the winter months. It is considered a weed because it competes with desirable grass species and can soon take over a lawn if left untreated.

Winter grass can be difficult to control since it produces a huge volume of seed that can germinate and spread the following year.

What does winter grass look like?

If you’re unfamiliar with what poa annua looks like, it grows rapidly, with drooping green leaves growing up to 15 centimetres in length. It’s characterised by its thin leaves that can either feel smooth or rough when touched.

Additionally, winter grass seeds germinate effortlessly, which leads to the emergence of small white seed heads in a triangular shape that can rapidly multiply at the end of the stems.

winter grass roots

Why is winter grass a problem?

Winter grass is a weed that competes with attractive grass species and can swiftly take over a lawn if left untreated. It grows quickly and generates a lot of seeds, making it tough to regulate.

Allowing winter grass to spread might result in an uneven and unappealing appearance in lawns. Furthermore, the seed heads can be dangerous to pets since they can become caught in their fur or cause discomfort if consumed. Winter grass is also less drought-tolerant than other grass species, rendering it more susceptible to harm during dry spells.

When does winter grass grow?

Winter grass, as one of the common lawn weeds, develops throughout the year’s cooler months, normally from April to September. Winter grass grows rapidly during this time, making it necessary to pay close attention to its growth patterns.

Winter grass can sprout in many areas as early as autumn and continue to thrive throughout the winter season, making it important to treat winter grass as soon as possible.

As an annual weed, winter grass completes its lifetime in a single year, with new plants growing from seed each season. Therefore, treating the entire lawn for winter grass is vital before new seeds take root.

Should I kill winter grass?

It is up to you and your lawn’s condition to decide whether to kill winter grass. If you like the look of your lawn and don’t mind the presence of winter grass, there may be no need to take action. However, if you want a homogeneous and well-kept lawn, you may need to control or eliminate winter grass.

Because of its prolific seed production and high growth rate, winter grass can be difficult to control. It can swiftly spread and dominate a lawn if left untreated. Hand-pulling, mowing, pesticides, and lawn repair are some ways to control winter grass. The intensity of the infestation will determine the most effective strategy, the type of grass in your yard, and your personal preferences.

How to get rid of winter grass in lawn

The growing stage of winter grass before it emerges from the soil is referred to as pre-emergent winter grass. Meanwhile, post-emergent winter grass refers to the growth stage of winter grass after it has emerged from the earth. 

The timing and administration of herbicides for eradicating pre and post-emergent winter grass differ. Below, we will walk you through this in greater detail so you can get the best results for your lawn!

Pre-emergent winter grass

Winter grass can be effectively prevented from sprouting and growing in your lawn by using pre-emergent herbicides. These herbicides prevent the growth of the plant’s roots and shoots before they emerge from the soil. Apply a pre-emergent herbicide to your lawn in late summer or early autumn before the winter grass germinates.

Make sure to properly follow the manufacturer’s directions and apply the herbicide evenly across the entire grass. You may need to apply numerous treatments throughout the season to establish adequate control. It is crucial to note that pre-emergent herbicides can also impair the growth of desirable grass species; thus they should only be used as advised and should not be over-applied. Furthermore, pre-emergent herbicides will not control existing winter grass growth. Therefore alternative means of weed control may be required.

Post-emergent winter grass

Post-emergent herbicides control established winter grass plants that have already emerged from the soil. These herbicides interfere with the plant’s growth and development, eventually killing it. Numerous post-emergent herbicides are on the market, each with a unique active ingredient and action method. Herbicides commonly used to manage winter grass include glyphosate, fluazifop, and sethoxydim.

To use a post-emergent herbicide, apply it directly to the winter grass plants, being careful not to come into touch with desirable plants. Follow the manufacturer’s directions and spray the herbicide evenly across the affected area. You may need to apply numerous applications if you want to control the winter grass completely. It is crucial to remember that post-emergent herbicides can also impact the growth of desirable grass species, so use them only as indicated and avoid over-application. Additionally, any dead winter grass plants may need to be physically removed to prevent them from reseeding and sprouting in the future.

How long does it take to kill winter grass?

Based on your specific situation, the time it will take to eliminate winter grass can vary. Factors such as the treatment method you choose and the size and maturity of the winter grass plants will play a role in determining the length of time it takes to get rid of them.

Generally, however, it may take several weeks to several months to fully eliminate winter grass from your lawn, depending on your treatment method and the extent of the infestation. If you want to achieve successful results, it’s important to consistently and thoroughly apply your chosen treatment method.

How to prevent winter grass from returning

Winter grass can be tricky to prevent, but there are several ways to achieve it. These can include:

  • Using pre-emergent herbicides in late summer or early autumn to stop winter grass from growing in the lawn.
  • Maintaining a lawn height of 5-7 cm to prevent winter grass from producing seeds and spreading.
  • Deep root growth can help your grass compete against winter grass and other weeds.
  • Fertilising the lawn with a balanced fertiliser in spring and autumn to help your grass develop strong roots and be healthy.
  • Winter grass prefers compacted, poorly drained soil – to improve soil structure and drainage, aerate and compost your lawn.
  • Proper mowing, watering, fertilising, and other lawn maintenance practices can help prevent winter grass from spreading.

Following these tips and maintaining your lawn will help avoid winter grass and keep it healthy and beautiful.


Does winter grass go away in summer?

Yes, winter grass typically dies off in summer as temperatures rise and the soil becomes too warm to grow. However, if not properly controlled, its seeds can remain in the soil and sprout again in the following winter.

Is winter grass killer safe on Kikuyu?

It depends on the specific winter grass killer being used. Some may be safe for use on Kikuyu grass, while others may damage or kill it. It’s important to carefully read the label and follow the instructions for any herbicide application.

Does winter grass have runners?

Yes, winter grass spreads through stolons or runners that grow horizontally above the ground and produce new plants at each node. This makes it particularly aggressive and difficult to control if left unchecked.