What to do about lingering winter grass

Have you had an explosion of Winter Grass in your lawn this Winter? Have you found that it's hanging around for longer into the Spring? You're not alone and probably as frustrated as the next person on what to do about it.

Winter grass (otherwise known as Poa Annua or Annual Bluegrass) is that annoying light green coloured grass that often comes up in your lawn during 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. The season for winter grass is typically from mid-April through to September.

Why is it hanging around?

By late September, most people are fed up with it, having endured it all Winter.  It's been a big season for Winter Grass this year, with many reports suggesting that it's lingering longer than usual. The reason for this is all to do with the weather, specifically soil temperature. We haven’t had a run of warm weather yet and so soil temperatures aren’t rising particularly quickly (averaging around the 14-degree mark), which is still within the tolerable limits for Winter Grass. With this in mind, it is likely that our little friends will hang around into October before succumbing to the arrival of the Spring warm weather.

What can you do about it?

The best, but probably unpalatable answer to this question is – nothing! (for now). I mentioned earlier that Poa was an annual weed. There will come a time very shortly when rising soil temperature alone will dispatch any Winter Grass remaining in your lawn. I’d say that by the end of October, it will be all but gone. While there are some residential post-emergent selective herbicides that you can use to treat Poa Annua, they take a fair amount of time to work – up to six weeks in some cases, meaning that the inevitable arrival of warmer weather will do the job before any application of chemicals will.

The secret about how to ensure that it doesn’t come back is what you do next. Anybody who’s experienced Poa Annua in their lawn will know that at the end of each winter, it leaves behind a significant amount of seed in the soil, ready for germination next Autumn when the cycle starts again. In this way, it tends to get worse each year.  If you want to stop it from returning, you’ll need to apply a pre-emergent herbicide called Spartan in February.

Pre-emergent control works on the principle that you control the weed's seeds before they germinate, therefore preventing the weed from taking its annual foothold.

Spartan only stops seeds from germinating (it doesn’t kill living weeds) and remains active in the soil for up to 16 weeks. For this reason, the timing of your applications is critical. The best time to apply is February, and then again in June. This way, you’ll prevent seed germinating in the lead-up to and all the way through Winter. 

If you've been battling Winter Grass for a few seasons, try Spartan. this coming Autumn.  It’s an absolute weapon against winter grass!