Winter might feel like a break from lawn work, but beneath the snow and frost, those of us in the South are noticing winter weeds in our lawns. Loathsome, obnoxious weeds!
In this guide, Super-Sod explains how to identify common winter weeds in lawns, why they appear when your grass is resting, and which control methods work. You’ll learn the difference between pre-emergent (prevention) and post-emergent weed control and when to treat with both types of products.
So, how do you tackle this problem of winter weeds? We've got plenty of advice for you on how to kill winter weeds.
White clover stands out in a dormant Bermuda lawn. This plant needs both pre- and post-emergent herbicide treatments for control. Photo by Kevin Kilgore, Regional Manager.
We’ll start with what NOT to do. Don't apply pre-emergent herbicide in January – it will be a waste of your time and money because the weeds have already germinated. It's a waste because pre-emergent treatments must be applied before weed seeds germinate.
If you see green weeds in your brown, dormant lawn, that means they have already germinated. By January, soil temperatures are too cold for weed germination, so any pre-emergent product applied will leach out of the soil before it can provide any benefit.
Poa annua grows fast! Make sure to remove it or mow it before all those seeds spread. Photo by Hillary Thompson, Communications Director.
Your best course of action is to work out your frustration by hand-pulling those pesky, pernicious, propagating weeds!
Properly identifying weeds helps determine how to control them. These are common winter weeds in the South. Click to see photos and learn more about each winter weed:
Common winter weeds (clockwise from top left): shiny cudweed, common chickweed, annual bluegrass, hairy bittercress, henbit, and dead nettle.
If you are wondering why you have weeds now, even though you did apply pre-emergent last fall, it may be one of two things:
👉 Pre-emergent is a powerful tool for combating weeds, so we've written an entire blog post on the ins and outs of using it. We cover timing, temperature, and when not to apply it in this article: Pre-emergent Herbicide is our #1 Trick for Weed Control.
Remember pre-emergent will not work on those weeds that have already sprouted. But you should prepare to apply pre-emergent in February when the Forsythia bushes flower (signaling the ground is warm enough for the pre-emergent to work). That application will reduce late spring/early summer weeds.
Super-Sod recommends a granular pre-emergent herbicide program as the most effective way to prevent winter weeds from fully germinating, thus killing weeds before you even see them. The best time to prevent winter weeds is in the fall: spread the granular pre-emergent herbicide from mid-September to mid-October. For weeds that you can see, spray a liquid post-emergent, selective herbicide directly on visible weeds when daytime temperatures are above 65 degrees. Carefully read the label to ensure the post-emergent herbicide is safe for your lawn type and that it specifically targets the weeds infesting it.
Super-Sod recommends hand-pulling weeds, mowing them to prevent flowering and seed production (thereby interrupting their lifecycle), and maintaining a routine pre-emergent herbicide program three times a year: in February, April, and September. Only as a backup, due to reduced liquid post-emergent herbicide efficacy during cold weather, does Super-Sod recommend spraying winter weeds with a post-emergent.
For the liquid post-emergent herbicide to work, the air temperature must be a little warmer than your typical winter day. Super-Sod recommends spraying winter weeds during warm spells when daytime temperatures are above 65 degrees Fahrenheit. Due to the colder weather, plants may not be actively growing, so a repeat application may be necessary.
For significantly reducing the amount of weeds you see, Super-Sod recommends following a three-times-a-year granular pre-emergent herbicide schedule: spread pre-emergent in February, April, and September. Pre-emergent is our number one trick for controlling weeds, so we've written an entire blog post covering the ins and outs of this technique; please read it here: Pre-emergent Herbicide is our #1 Trick for Weed Control.
Our master document about weed control can be found here: Weed Control for Lawns.
Still unsure what a post-emergent is vs. a pre-emergent? Read our article on Pre-Emergent, Post-Emergent, and Weed & Feed: What's the Difference?
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