What Is Quackgrass and How Do I Get Rid of It?
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Controlling and getting rid of quackgrass takes persistence, but it can be done. Here's how to kill the invasive perennial before it takes over your lawn.
Despite its whimsical name, quackgrass is a formidable enemy that can take over a lawn quickly. Its strong, deep root system can grow into separate plant clumps if split, and no selective herbicide will kill it while leaving your lawn unaffected. That’s why quackgrass — also known as couch grass, twitch, quick grass, quitch grass, dog grass, scutch grass and witchgrass — is considered one of the hardest weeds to eradicate.
If you spot clumps of quick-sprouting grass that is taller than your turf, with broad rough leaves and thick white roots, you may have a quackgrass invasion. Read on to learn how to identify this aggressive invader and eradicate it for good.
What Is Quackgrass?
Quackgrass vs Crabgrass
“The best way to identify quackgrass is to look for clasping auricles [ear-like projections] that are located near the base of the blade right before it reaches the stem,” Wagner says. “Unlike crabgrass, quackgrass uses rhizomes, or underground runners, to spread. These rhizomes also produce chemicals that stunt the growth of other plants so that the quackgrass can outcompete them and take their place.”
This chemical production, known as allelopathy, is the weed’s “superpower,” according to Bob Mann, a lawn care expert with the National Association of Landscape Professionals. That results in patches of quackgrass that stand out from surrounding grasses. Because the underground rhizome system splits into separate plants, quackgrass is particularly hard to get rid of.
Is Quackgrass Safe?
Quackgrass may quickly choke your turfgrass, but Mann says it doesn’t cause skin irritations or pose other risks to humans or pets. In fact, quackgrass will attract animals like small birds who feast on the seeds.
Unfortunately, animals also tend to spread the seeds in your lawn via their droppings, thus infesting larger areas. Each quackgrass plant produces about 25 seeds, and they can stay viable in the soil for up to five years.
How to Kill Quackgrass
“One of the most effective ways to control this weed is with the application of a non-selective herbicide that contains glyphosate or some other alternative to glyphosate,” Wagner says. “Non-selective herbicides will kill any vegetation it comes in contact with, so be careful not to get it on the grass or other desirable plants.”
Mann agrees. “There’s an old saying in the turfgrass business: The very best herbicide of all is a dense stand of vigorously growing turfgrass,” he says. “This is doubly true as it relates to quackgrass.” If an area of your lawn or garden becomes badly infested, you may need to treat it and then replant the entire area.
If you do decide to tackle your quackgrass with an herbicide, follow these steps:
Remove any plants you want to protect from the immediate area, if possible.
Pull up as much quackgrass as you can, being careful not to spread seeds by bagging the weeds in paper or plastic.
Check the soil carefully for any traces of the quackgrass root system and remove.
Treat the affected area with a non-selective herbicide.
Wait a week, then treat the soil again.
Allow any quackgrass left to die, then clear and reseed the area.
Once you’ve stopped quackgrass in its tracks, you’ll need to be vigilant to keep this persistent weed away. Here are some steps to keep your lawn quackgrass-free for good:
Most weeds can be controlled by following best management practices so your lawn is thick and healthy enough to ward off an invasion. Apply a nitrogen fertilizer to choke out the quackgrass and enable your turfgrasses to outcompete weeds.
Monitor your lawn weekly during the growing season to ensure quackgrass has not returned, especially in soils where the weed thrives: loamy (equal parts sand and silt with not much clay) or sandy (primarily sand with little silt and clay).
Check any plants you bring home from stores or nurseries so you don’t accidentally reintroduce quackgrass. Remove the plant and roots completely if you discover it in the pot or planter.
If you do spot a resurgence in your yard, act quickly to limit the spread by following the steps above.