There are currently two products on the market that you will need to pay close attention to if you plan to make a herbicide treatment to your lawn. The confusion is that Roundup is a product that has been on the market since the early 1970’s and contains glyphosate as the active ingredient. Roundup is a non-selective herbicide that kills any green plant to which it is applied. With a lawn application this statement would be accurate, but we do have some weeds in cereal grain fields that are resistant to glyphosate. There many generic products which contain glyphosate and you need to check the label for the amount of active ingredient when comparing products and prices.
Roundup for Lawns is a totally different product which does not contain glyphosate. To make it even more confusing there is a northern and a southern version of this product for different grass options. The northern version of Roundup for Lawns contains MCPA, quinclorac, dicamba and sulfentrazone. These active ingredients can be found in many lawn herbicides in different combinations for various weed control options. MCPA, 2,4-D and dicamba are products used to control broad leaf weeds such as dandelion, ground ivy or mallow. Quinclorac is often added to provide post-emergent control of crabgrass. Sulfentrazone is a product that provides control of sedges such as yellow nut sedge as well as some broadleaf weeds. All of the active ingredients previously mentioned will not kill your lawn grasses.
Selecting the wrong Roundup will result in very different outcomes. Roundup will leave you with a brown dead lawn, where Roundup for Lawns will control selective weeds and not harm your grass. However both of these products can be harmful to many of your landscape plants if applied to them. So it is critical to know what active ingredients are in the product, not the product name itself. As always READ THE LABEL! The label is the law and must be followed when using any herbicide due to the active ingredient toxicity levels, application rates, personnel protective equipment, and re-entry intervals.
Accidentally used Roundup for northern grass on centipede lawn. Am I screwed?
Pretty much, depending on the strength of your mix. But you’ll get a better extent of the damage at around 3 days. I run an irrigation and landscape store. I accidentally ordered Roundup Northern instead of Southern – was too distracted with the lower price. Then sold those to customers. Centipede grass grass damage was less harrowing compared to what it did to Saint Augustine grass. Fortunately, our landscaper customers do get paid more to install new grass. So while they were quite irate, I had to give them discounted prices on sod orders to mitigate it.