How can I kill quack grass in my lawn?
I have some quack grass interspersed in my Kentucky blue grass lawn. How can I get rid of the quack grass? Thanks.
Sevier County Utah
Unfortunately, control of grassy weeds like quackgrass in existing lawns is one of the more challenging weed control problems that exists for homeowners and landscape managers. Quackgrass is a perennial plant that spreads by rhizomes (underground stems), making control difficult.
The best control will be achieved by using a non-selective herbicide such as glyphosate (active ingredient in RoundUp). You can either spray out the area, using multiple applications, completely or attempt to apply the product only to the quackgrass. Though difficult, this is not impossible. You should mow, wait 3-4 days and then wipe the herbicide on the quackgrass blades using either a paint brush or a sponge mop. The quackgrass should be taller than the desired grasses at this point, allowing you to contact only the weedy grasses.
Since some lateral buds on the rhizomes are dormant even when there are actively growing leaves, you'll likely need to make multiple applications. You can also force the buds out of dormancy if you apply nitrogen fertilizer to the area before using an herbicide. This will help to kill the entire plant. You will need to repeat the application every 30-45 days, but should gain control over time.