Act now to control winter grass!

Author: Stefan Palm   Date Posted: 27 February 2019 

Did you know that there is a herbicide that you can apply now which will stop winter grass from coming up in winter? Sounds hard to believe doesn't it!

Winter grass (otherwise known as Poa annua or annual blue grass) is that annoying light green coloured grass that comes up in your lawn every winter.

If you have it, you’ll know exactly what I’m talking about. It produces lots of seeds and has a white cotton like root zone. It’s easy to pull out but there is always so much of it and more often than not, as soon as you pull it out, more seems to grow back. The most annoying thing about this weed by far is that it gets worse every year! This is because wintergrass produces large amounts of seed, which fall to the ground ready to germinate next year. If each wintergrass plant produced 50 seeds, you can see how quickly this plant can get out of control.

Now that we know what we’re dealing with, the big question is how do you get rid of it and how do you successfully keep it out. There are 2 methods for controlling winter grass. The first is post-emergent control and the second is pre-emergent control.

Post emergent control is where you selectively poison out the weed after it germinates (ie during the autumn and winter months). There are products such as Kerb and David Grays Wintergrass Killer that are designed to selectively control wintergrass in couch during winter, when you can see the weed. These products only work if they are applied exactly as directed and can take a considerable amount of time to work. Control can take anywhere from 2 weeks to 2 months which can frustrating because there are often successive waves of wintergrass that will germinate giving the impression that your control measures are not working. If applied too late into the winter, it can be hard to get a result at all. 

Pre-emergent control works on the principle that you control the seed before it germinates which I have to say is a far better way to approach to this problem. There are products that you can apply such as Embargo and Pendi Pro that will literally stop the wintergrass seed from germinating meaning you won't see it come winter.  

Pendi Pro:

Pendi pro is a pre emergent herbicide combined with a granular fertiliser. It comes in a 20kg bag and can be applied with a spreader: Suitable for Couch, Kikuyu, Zoyzia and kentucky bluegrass. Do not use on buffalo. Apply every 6 weeks from feb/march through to August. Covers 600m2 


Embargo is a liquid pre emergent herbidice which is sprayed on. Suitable for couch, kikuyu and buffalo. Covers 1000m2. Apply every 16 weeks from feb.march through to August.

The best time of year to do this is a few months before the weeds start to germinate – i.e. February to March.  The chemical stays in the soil for between 6  and 16 weeks (depending on which product you use and literally stops the wintergrass seed in the soil from germinating.  If you've been battling with it for a few seasons, try Pendi Pro or Embargo. While they are expensive to buy, they are an absoulte weapon against winter grass. 

Comments (21)

Winter grass

By: on 6 July 2019
Is it too late to use Embargo in July?

Paul Munns Instant Lawn Response
Hi Helen, If your using Embargo to control winter grass, then yes - it is too late to apply in July. The best time to apply is in February to stop next seasons seeds from germinating.

Winter grass

By: on 24 May 2019
I’ve just sprayed embargo knowing the winter grass has started to germinate. I will persist again in 16-18 weeks. If this isn’t successful is there a selective weed killer that can knock it out whilst established ?

Paul Munns Instant Lawn Response
Hey Adam, Even though you were late in applying Embargo, it was the right thing to do and it will round up most of the seeds. If you have couch or buffalo, you can use a selective herbicide called David Grays Wintergrass killer to knock off the ones that have already germinated. If you have Kikuyu, there is no selective herbicide that you can use meaning you'll have to hit it again next year in March with Embargo to prevent further germination

Starting now 13 April

By: on 13 April 2019
Hi there.... coming a little late to the party... is there any point to starting the pre-emergent now? i.e. halfway through April? Also wondered if it would be worth applying directly to soil where I want to grow some grass (planting spring /summer potentially). why does it come in such large amounts? I only have small areas of lawn and the area I want to plant lawn is also quite small.

Paul Munns Instant Lawn Response
Hey Deborah, April is late to be applying pre emergent herbicides. Ideally you should start in February or March but having said that, it is an unusual season this year with its dry and hot conditions persisting late. This means that weeds like wintergrass are also late in germinating. If you have not had any germination of wintergrass yet, then it is still OK to apply Embargo. You can use Embargo directly on the soil to prevent certain weeds from germinating however it has a 16 week residual effect in the soil meaning you couldn't sow any grass seed for at least that period. To be safe, I would allow 20 weeks between application and re-seeding or turfing. The reason that these types of chemicals cover such large areas is that they are produced for commercial / large scale areas rather than domestic lawns. Having said that, until 6 months ago, Embargo (one of the better pre-emergents) was only available in 5L pack sizes or larger! The release of a 500ml bottle has made it accessible to domestic customers. While it is still expensive to buy, it is a the only truly effective way to tackle winter grass.

Longevity of Embargo

By: on 11 April 2019
With only a small area of lawn I don't really need a large bag of Embargo. Assuming that you don't supply smaller amounts will the product keep and still be fully potent and useable after several years of storage?

Paul Munns Instant Lawn Response
Hey Chris, The 500ml pack size is the smallest size Embargo comes in. It will keep for years to come though. Up until recently, the smallest size was 5 Litres so this newly released size is much more convenient for smaller areas. If you're looking to clean up weeds like winter grass, Embargo is outstanding. It genuinely works.

Embaro and Dave Grays wintergrass killer

By: on 21 March 2019
Hi , can you apply Embargo and Dave Grays together? I have areas that have Wintergrass starting already but others that have not yet.

Paul Munns Instant Lawn Response
Hey Alex, I would not advise you to mix chemicals together, even though you are targeting the same weed. Chemical concoctions can have damaging effects. Allow 3 weeks between applications and start with the Embargo


By: on 20 March 2019
Can you tell me please how much water do I mix with my embargo herbicide when I am spraying on my lawn?

Paul Munns Instant Lawn Response
Hi Marian, You mix 5ml of Embargo per litre of water and then spray that mix over 10 square metres. After applying, water in with around half an hour on your sprinkler system.

Rhizomatus Tall Fescue lawn with wintergrass

By: on 16 March 2019
Paul and Stefan could you please be as specific as possible re the potential damage using embargo or pendi pro on a Rhizomatus Tall Fescue lawn . I will need at least 2 bags if it is safe to use . Can call in to your store to pick up. If I chose embargo I have a boom spray , would that be the best way to spray ? Regards Rob Gilbert Snows Rd Stirling . Ph 0417834745

Paul Munns Instant Lawn Response
Hi Rob, Unfortunately neither product mentions Tall Fescue as a suitable situation. Neither product specifically excludes it either in the restraints section of the label. It is unusual that neither product mentions Tall Fescue however because it is absent, I can't recommend for you. Happy to have a chat about this with you - Our number is 8298 0555

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