How to rid your lawn of quackgrass (and all growing beds, too)

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Among the weeds that invade flowerbeds, lawns, or vegetable gardens, quackgrass (Agropyron repens or Elymus repens) is surely one of the toughest. The reason why couch grass (another name for it) always comes back is because it’s not uprooted properly. Here are all our tips for removing quack grass and preventing its return.

For further reading:

• Weeds and health benefits
• Useful weeds or beneficial plants for the vegetable garden

What exactly is quackgrass?

Surely, couch grass is a weed or bad plant. But it is also a perennial herbaceous plant with rhizomes that grows everywhere in the world, at all altitudes, and in all climates. In a nutshell, it’s very tough and highly invasive.

Indeed, the subterranean rhizome spreads, and branches out aggressively. It produces long lateral stolons that penetrate several feet into the soil (up to 1 meter). This mode of multiplication earns it a well-deserved reputation as an invasive plant.

It gets another of its common names, dog grass, from the shape of its rhizomes that look like dog’s teeth.

Benefits of couch grass

• Cats and dogs eat couch grass to purge their stomachs when they’ve eaten something wrong
• Dried quackgrass roots are known for their diuretic properties and are effective against urinary infections.

Identifying quackgrass in the lawn

It’s not always easy to recognize couch grass, in the lawn or flowerbeds, since it looks just like… grass!

However, couch grass leaves are dark green, and notably rough on the front, smooth on the back. A well-marked groove runs down the length of the leaves. These leaves show some stiffness.

As for the stems, they are straight, and bear flat spikes, composed of spikelets, which bloom in early summer and midsummer. Couch grass produces seeds that don’t really germinate very easily… but this grass definitely manages in other ways!

Don’t do this to kill quackgrass

Usual weed-killing tricks always backfire when dealing with quackgrass. Indeed, in terms of weeding, couch grass should receive special treatment. And certain habits should be forgotten to get rid of this weed:

• Never use the rototiller to turn soil where couch grass grows. Blades will cut rhizomes up… and spread them throughout the plot. Very bad idea!
• Do not hoe or weed couch grass clumps because this breaks roots up. Each portion then becomes a new, aggressively spreading clump.
• Never weed by burning couch grass. It’s useless because roots remain alive underground.
• Avoid using chemical herbicides.  Apart from being harmful to soil and cultivated plants, they can’t target weeds specifically. Everything gets hurt!

As for mulching, though effective in preventing the spread of many weeds, won’t work for couch grass. Indeed, its perennial nature allows it to survive while annuals cannot germinate and grow due to mulching.

Weeding methods against quackgrass: what works and what backfires

Couch grass reacts to weeding quite differently from ordinary weeds. Here is what each common method actually does to its rhizomes.

The rule is simple: anything that cuts the rhizome multiplies the problem, anything that lifts it whole solves it.

Get rid of quackgrass: the definitive guide

First off, let’s clarify one thing: getting rid of quackgrass will make you break a sweat. This weed is tenacious!

• Step 1:  weed with a spading fork or a broadfork. To reach deep rhizomes, you need to loosen the soil up without tearing roots. These tools lift the root clump up as a whole, and all that remains is to pull it out by grabbing the collar or root crown. Perform such weeding in fall, when soil is softer. You’ll have to do the same thing in the lawn.
• Sow green manure to prevent couch grass from settling in the vegetable garden. Having a plant in place already will stop it from settling in both above and below the soil surface.
• Dispose of quackgrass at a professionally-managed waste site, so that they may burn it or find other solutions. Don’t try to compost it at home, or you’ll be in for a sorry surprise once it starts popping up everywhere!

Tips and Tricks to slow its return

The tips and tricks we mention hereafter are purely for the sake of completeness, because their effectiveness has never yet been formally proven. But many say they seem to work.

Here goes! Planting French marigold (Tagetes) is said to be effective against quackgrass. French marigold roots seem to have a repellent effect on this invasive grass, as do the roots of common marigold (calendula), and possibly those of nasturtium.

Cut the flat spikes down before they ripen, so no seed is added to the soil.