Controlling Wintergrass in Lawn

Author: Stefan Palm   Date Posted: 16 May 2016 

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, it 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 a crazy amount of seeds, 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.

If you’ve been at war with this weed you’ve no doubt tried a few of the chemicals designed to selectively kill it at which point you’ve probably also discovered that some of these products can be a bit hit and miss.

OK, so 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 when you can actually see it growing in your lawn (ie during the winter months). There are products such as Kerb and David Grays Wintergrass Killer that are designed to selectively control wintergrass in couch. These products only work if they are applied exactly as directed and don’t specifically kill wintergrass but rather retard its growth and prevent the weed from seeding (reducing its ability to reproduce itself next winter). It can be a frustrating method because there are often successive waves of wintergrass that will germinate giving the impression that your control measures are not working.

Pre-emergent control works on the principle that you control the seed before it germinates. There are products that you can apply such as Embargo (for couch, kikuyu and buffalo) and Pendi Pro (for couch) that stop the seed from germinating properly. The best time of year to do this is when there are no wintergrass weeds present – eg January to March and if done properly will result in very little to no wintergrass seed popping up in your lawn come winter. It is by far the best way to control wintergrass.

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