Act now to control winter grass!

Author: Stefan Palm   Date Posted: 21 March 2022 

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 but you need to act quickly as time is running out.

Winter grass (otherwise known as Poa annua or annual bluegrass) is that annoying light green coloured grass that comes up in your lawn every winter -  It's an annual weed meaning it only lives for a short time and only comes up at a certain time of the year. For winter grass, its season is typically from mid-April through to September.

You’ll know exactly what I’m talking about if you have it. 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 is that it gets worse every year! This is because winter grass produces large amounts of seed, which fall to the ground ready to germinate next year. If each winter grass plant produced 50 seeds, you could see how quickly this plant could get out of control.

The big question is, how do you get rid of it, and how do you successfully keep it out. There are two methods for controlling winter grass. The first is post-emergent control, and the second is pre-emergent control.

Post-emergent control

This is where you selectively poison the weed after it germinates (i.e. during the Autumn and Winter months). There are products such as Kerb and David Grays Wintergrass Killer that are designed to selectively control winter grass 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 be frustrating because there are often successive waves of winter grass 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

This works on the principle that you control the weed's seed before it germinates, which I have to say is a far better way to approach this problem. You can apply products such as Spartan and Pendi Pro that will act as a preventative treatment and literally stop the winter grass seed from germinating, meaning you won't see it come winter.  

Spartan

Spartan is a pre-emergent herbicide that comes as a liquid and is sprayed on your lawn. Apply every 16 weeks from February through to August. It is effective against major annual grass weeds in turf during winter and summer.  Being an unscheduled chemical, it's safe for use in public areas. 

  • A 500ml bottle covers up to 1600m2
  • Safe for use on most lawns, including Couch, Kikuyu and Buffalo
  • Apply every 16 weeks

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: Apply every six weeks from February through to August. 

  • 20kg covers 600m2
  • Safe for use on Couch, Kikuyu and zoysia lawns. Do not use on buffalo
  • Apply every six weeks

The one you choose will depend on your lawn type (e.g., you can't use Pendi Pro on buffalo). It will also depend on whether you prefer spraying a liquid over your lawn or spreading out a coated fertiliser. My preference is Spartan as it lasts longer in the soil and covers a larger area.

When to Apply pre-emergent herbicides

The best time of year to do this is the months leading up to when the weeds start to germinate – i.e. February to March.  It has been a warm and dry season so far this year, and so the window to apply has been extended. As soon as we get a couple of successive rains, combined with cooler weather, winter grass seeds will begin to germinate. It is critically important that these herbicides are sprayed before the weed emerges. In other words, if you can see winter grass growing in your lawn, then it is too late to apply this season. The chemical stays in the soil for between 6 and 16 weeks (depending on which product you use) and literally stops the winter grass seed in the ground from germinating. 

If you've been battling it for a few seasons, try Spartan or Pendi Pro. While they are expensive to buy, they are an absolute weapon against winter grass. 


Comments (45)

Winter grass

By: on 25 March 2022
Hi We have couch and in winter it needs infrequent mowing. The dreaded Poa emerges and is very obvious, even before going to seed. Our lawn is only about 70m2 and I patrol it once every week or 2 and pull up up the invader. We had instant turf rolled out about 10 years ago and the first winter I literally pulled up thousands of Poa. You can tell I'm retired - too much time on my hands.

Paul Munns Instant Lawn Response
Hi Brendan Thanks for your message To prevent winter grass from germinating in Winter you can use one of two pre-emergent products we stock. We have Pendi Pro which is a fertiliser and pre-emergent in one or we have Spartan which is a pre-emergent by itself. These can be applied now as long as no Winter grass has germinated. Thank you

Winter grass

By: on 20 August 2021
Hi can you tell me is there any product l can use on tall fescue lawn to kill winter grass. Regards sue

Paul Munns Instant Lawn Response
Hi Sue Thanks for your enquiry Unfortunately there isn't anything selective to control Winter Grass in Tall Fescue lawns

Tall fescue and winter grass

By: on 12 August 2021
Hello, I see in the above comments there is no way to Control winter grass in tall fescue. Will winter grass die off after winter or should I be removing it as it appears? Or open to other suggestions.

Paul Munns Instant Lawn Response
Hello Mat Unfortunately there isn't anything selective to control Winter grass in Tall Fescue. I would recommend to get it all out (as much as possible) Winter grass will die off in the heat of Spring and Summer but will drop the seeds in the soil and germinate next winter Thank you

poa weed

By: on 5 July 2021
Paul - I have a santa ana lawn . Is it safe to use spartan in this lawn and when is it best used . Is it too late now

Paul Munns Instant Lawn Response
Hi Alan Thanks for your query Spartan is safe to use on Santa Ana. Best to apply it in Feb/March next year. Bit too late now Thank you

Is it pet safe

By: on 14 June 2021
Is this product pet safe and how long after application can pets return to the area

Paul Munns Instant Lawn Response
Hi James Thanks for your query Yes, it is ok to use if you have pets. I would just recommend to allow drying time of the product before pets go back on the area Thank you

Winter Grass

By: on 10 April 2021
Hi I purchased Embargo from you last year and had great success with it. Have used again this year. For how many years should I use it do you think to ensure no more winter grass? Regards, Dianne

Paul Munns Instant Lawn Response
Hi Dianne Thanks for your enquiry I would recommend applying it every year. You never know if a bird or wind etc may cause it to come back in your lawn

Embargo March 21 /2021

By: on 21 March 2021
Hi Paul, is it too late to use Embargo to kill Winter grass in Sir Walter lawn. Regards, Margaret.

Paul Munns Instant Lawn Response
Hi Margaret Thanks for your enquiry It's not too late as long as the Winter Grass hasn't germinated Unfortunately we no longer sell the Embargo. We have a new product called Spartan which you can use as a pre-emergent

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