Crabgrass Vs. Quackgrass | How To Tell The Difference & Which Is Worse?

Grassy weeds can be a significant hurdle to establishing a lush green uniform lawn. These protrude from the ground and create an unsightly mess in your grass. Because of their resilience and hardiness, some lawn owners simply quit and settle for these clumpy-looking weedy grasses, but don’t let this be you. Sometimes the reason why you cannot get rid of crabgrass is that it is not crabgrass at all.

Crabgrass Vs. Quackgrass
Quackgrass is a cool-season perennial, whereas crabgrass is a warm-season annual plant.

Photo by NY State IPM

Quackgrass and crabgrass look somewhat alike, and when they square off, it’s like watching a heavyweight fight between two invasive types of grass that can ruin your once-perfect, velvety lawn. Unfortunately, you won’t be able to eliminate these hardy, clumpy grasses even with the best herbicides if you treat one for the other.

So, what is the difference between crabgrass and quackgrass?

Quackgrass is a cool-season perennial, whereas crabgrass is a warm-season perennial. Roots of crabgrass from a shallow crab-like structure and the roots of quackgrass from rhizomes that spread horizontally and deeply into the ground. Differences aside, both of these clump-forming pesky weeds have a difficult time growing in lawns that are dense and thickly shaded.

This article explains how to distinguish between quackgrass & crabgrass, so you know which weed you are dealing with and what is the proper treatment for your problem!

Crabgrass

Crabgrass
Crabgrass is yellowish-green to lime green, making it easy to recognize on a lawn.

Photo by NY State IPM

As an annual, crabgrass sprouts from seeds in the spring. However, if you live in the north, you will have to wait until late May to see it. Being opportunistic, crabgrass takes over any barren areas where nothing else grows. It doesn’t care about pH, fertility, or moisture; therefore, it quickly takes over places of a lawn where the grass isn’t dense or strong.

In the winter, as crabgrass dies, the lawn will have patches of flat, brown blades. Every year, crabgrass grows new plants from seeds, and the thousands of seeds that are produced by crabgrass plants can survive and remain viable for years.

Crabgrass Identification

This weed gets its name from the way its roots are structured. The roots spread across a wide area below the surface of the ground, and the stem emerges from the middle of the clump. This makes it look like the legs of a crab. 

The weed is so challenging to control and difficult to eradicate that the mere prospect of dealing with it is enough to make some gardeners shudder. Here is how you can identify this annoying weedy grass:

  • The stem of crabgrass is curled, giving it a rounded vernation, while the leaves are lime green and have a coarse texture.
  • When young, crabgrass is bright green and occasionally displays a purple hue on the stems.
  • The individual strands of grass emerge unhindered from the steam and advance outward.
  • As it matures, the stems get heavier and fall, revealing a pattern in the form of a star in the center.
  • When the leaves are still young, they have the thickness of a pencil.
  • Crabgrass seed heads resemble fingers and have spikes that grow from several locations at the top of the stems.

RELATED: How To Get Rid Of Crabgrass For Good? | Prevent Crabgrass From Returning

Quackgrass

Quackgrass
Mature quackgrass plants can reach up to a height of one meter or more.

Photo by Matt Lavin

Other names for quackgrass include couch grass, Agropyron repens, and Elymus repens. It is a cold-resistant perennial weed, which means that it will continue to return year after year. In some climates, it actually remains green all year long. It is one of the earliest grasses to emerge from their winter dormancy each year. 

Quackgrass mainly relies on the nutrients stored in its roots. It reproduces through rhizomes and seeds. Rhizomes are the long stems that grow underground, and some of them can be found as deep as six feet below the ground’s surface.

Quackgrass Identification

Quackgrass (quack quack) is a weedy grass that is undoubtedly offended whenever it is referred to as crabgrass. Given that Quackgrass and Crabgrass have several similar traits, it is understandable that people often mistake one for the other.

However, quackgrass is quite distinct from crabgrass and grows in an upright position. Also, its roots are white and robust. Here is how you can identify quackgrass easily:

  • The auricles, which resemble claw-like structures and wrap around the stem near the top of the sheath, are the easiest way to recognize quackgrass.
  • It also has creeping rhizomes with pointed tips that develop in a horizontal direction underground.
  • Stem sheaths and seedling leaves are both hairless in quackgrass.
  • The grass seeds are long and thin.
  • Quackgrass plants that have reached maturity can grow to be up to one meter tall.

Quackgrass Vs. Crabgrass | Differences

Which one is harming your lawn, crabgrass or quackgrass? You’ll need to know the difference before you can get rid of these weeds on your lawn. The differences between crabgrass and quackgrass are laid forth in the table below:

QuackgrassCrabgrass
Cool-season perennialWarm-season annual
It forms underground rhizomes that continuously grow and are whiteIt creates a shallow root system that resembles the legs of a crab
Leaves of quackgrass are hooked around the stem with the help of auriclesThe leaves of crabgrass grow independently of the stem
Quackgrass stems develop singly as they spread throughout a regionThe shoots of the crabgrass grow from star-shaped stumps
Crabgrass is difficult to control and needs chemical, mechanical and preventative measurementsThe best way to control crabgrass is to limit the seed spread and break its lifecycle
Short-term quackgrass control includes mowing close to the ground and spraying in early springshort  term control for crabgrass includes bagging its clippings in summer
Long Term control includes maintaining a healthy turfLong Term control includes maintaining a healthy turf
Mow and spray your lawn consistentlyUse pre-emergents for effective control
Encourage the development of desirable grasses for better controlUse post-emergent herbicides before the crabgrass plants set seeds

Quackgrass Vs. Crabgrass | Pictures

crabgrass vs quackgrass
Crabgrass has broad leaves and a low-lying growth habit.

Photo by NY State IPM

In addition, crabgrass roots are shallow and close to the lawn surface.

Quackgrass Vs. Crabgrass  Pictures2
Quackgrass leaves are relatively narrow, and it has an upright growth habit.

Photo by Marina Thompson

In addition, quackgrass roots are pretty deep and white in color.

Crabgrass Control

Crabgrass Control
Solarization is an excellent way to kill crabgrass without the use of chemicals.

Photo by RAHUL143

The elimination of crabgrass has resulted in the development of an entire product category known as pre-emergent crabgrass killers. The chemical-based alternatives have some severe downsides even though they work well. Some pre-emergents have an effect on all grass seeds for up to twelve weeks following application. As a result, the growth of both crabgrass and desirable seeds is prevented.

Pre-emergent Herbicides

Crabgrass is an annual plant, and the good news is that the winter frosts will always destroy it. So, if you have found crabgrass on your lawn, it is best to leave it alone and then use a pre-emergent herbicide early in the following spring. This will prevent any seeds that were left over from the previous year from developing and spreading the crabgrass weed. Applying a pre-emergent product to your lawn in the spring is a crucial step to take, especially if you have a problem with crabgrass that keeps coming back.

Post-emergent Herbicides

Controlling crabgrass once it has emerged with a post-emergent herbicide is typically more successful when applied to the still young plants that have not yet tillered. Unfortunately, the postemergence control of crabgrass becomes increasingly difficult as the plant matures, and it is necessary to apply numerous treatments in order to accomplish control.

Quinclorac (a post-emergent herbicide) is relatively safe when applied to young seedlings and offers effective control of crabgrass at nearly any growth stage (seedling or gorilla-sized). Quinclorac is also a good choice for controlling certain broadleaves, such as white clover and dandelion, when used on its own.

Crabgrass Control With Mulch

Mulching with wood products, composted materials, or synthetic landscape fabrics inhibits crabgrass development by obstructing the sunlight required for germination and growth. Coarse mulch may need to be 3 to 6 inches deep, whereas finer mulch may only need to be 2 to 3 inches deep to suppress crabgrass completely.

If crabgrass seeds are starting to germinate in the mulch, moving it about with a rake will help prevent the seedlings from becoming established. Hand-pull any escaping crabgrass plants before they set seed.

Control Crabgrass With Solarization

In hot weather, covering weeds like crabgrass with clear, transparent plastic or a sheet to let the sun’s heat desiccate and kill them is a natural way to get rid of them. Any areas of your lawn where crabgrass is growing in abundance can be solarized.

Because solarization takes advantage of the sun’s natural heat, crabgrass can be permanently eradicated without using chemicals. Summer is the best time to solarize crabgrass when the heat of the sun is at its maximum.

Crabgrass Cultural Control

Crabgrass is a weed that spreads and reproduces primarily through the seeds; hence any cultural initiatives that lower seed germination would reduce crabgrass occurrences. Cultural practices that boost turfgrass health also lessen the risk of crabgrass invasion.

These include choosing the best turf species for your region, utilizing the proper mowing height for your particular turf, overseeding to maintain turfgrass thickness, fertilizing at the right time of year, and using the right irrigation.

Quackgrass Control

crabgrass vs quackgrass - Quackgrass Control
Mowing at 3 inches can help eliminate quackgrass organically, although slowly.

Photo by Cindy Shebley

Because it is a perennial that grows during the cool season, quackgrass is very hard to eliminate. It is especially common in grasses that thrive during the cool seasons, such as tall fescue, ryegrass, and bluegrass.

When the conditions shift and become favorable, they will begin to develop and quickly spread throughout your lawn. The root system becomes significantly more robust during the winter.

Crabgrass control needs the integration of chemical, mechanical and preventive measures. Here are a few of them:

Quackgrass Herbicides

Applying a non-selective herbicide containing the active ingredient glyphosate is one method that can be used to get rid of quack grass. Be careful because the herbicide glyphosate can also destroy beneficial grasses and unwanted weeds. Just the areas affected by Quack grass should have the herbicide applied to them.

To minimize damage to desirable grass, mow the lawn first, then wait three to four days before spraying the Glyphosate onto the tall-growing Quack grass using a  sponge mop, paintbrush, or applicator.

Mechanical Quackgrass Control

Digging up the problematic areas, removing several inches of soil, replacing it with new topsoil, and reseeding are all mechanical approaches. However, the rhizomes of quackgrass can grow anywhere from six to eight feet deep in the earth, and it is possible that these rhizomes could “push” new plants to the surface.

Solarization is another way to control quackgrass. This technique involves covering the quackgrass regions with clear plastic that are firmly attached to the ground.

The plastic will aid in keeping the heat concentrated towards the soil’s surface, hopefully rendering the plant matter inert. After removing the plastic, reseed the area.

Quackgrass Cultural Control

Another method to control quackgrass is to support healthy grass growth through the use of good cultural practices. These practices include things like keeping proper soil fertility, selecting grass kinds that are appropriate for your area, and frequently scouting for and treating pests. Cutting the grass at the height of around three inches is an excellent cultural method for organically and gradually eliminating quackgrass as well.

Quackgrass & Crabgrass Prevention

Once you’ve stopped crabgrass or quackgrass in their tracks, you’ll need to exercise caution to keep these tenacious weeds from returning. So here are some strategies to keep these weeds out of your lawn permanently.

  • If you notice that the problem has returned to your yard, you should move swiftly to treat it using one of the methods described above.
  • Applying a nitrogen fertilizer can help your turfgrasses compete more effectively with weeds and simultaneously eliminate crabgrass and quackgrass from your lawn.
  • Be sure to inspect any plants you buy from stores or nurseries and bring them inside your home to prevent the unintentional spread of crabgrass or quackgrass.
  • Check your lawn once a week to make sure that crabgrass and quackgrass have not resurfaced, particularly in soils that are ideal for the growth of the weeds.

RELATED: When To Apply A Crabgrass Preventer For The Best Results? A Beginners’ Guide

Conclusion | Quackgrass Vs. Crabgrass

Even a skilled lawnmower finds it challenging to eliminate these weeds. These weedy grasses can avoid some of the sharpest equipment since they are resistant and clumpy. Some lawn owners choose to ignore these weeds because they might be challenging to get rid of at times. However, it might not be necessary if you know how to spot them and get rid of these troublemakers. 

Nonetheless, in order to completely eliminate these pesky weeds, the first step is to tell one from the other. Understanding which grass you are dealing with will help you choose the best strategy because getting rid of the two types of grass is quite different.

Frequently Asked Questions (FAQs)

Is there a grass that looks like crabgrass?

If you are in the Midwest during the early stages of spring and you encounter something that appears to be crabgrass, you can be almost sure that it is not crabgrass. Quackgrass and old-fashioned Tall Fescue are two types of grass that are frequently confused for crabgrass.

How do you get rid of crabgrass permanently?

Applying a selective post-emergent crabgrass killer that contains quinclorac is the most effective method for getting rid of crabgrass that is actively growing in your lawn. It will eliminate the weed without harming grasses on the lawn such as Bermuda, Zoysia, or Fescue; however, it should not be used on St. Augustine or Floratam.

How do you fight quackgrass?

Spraying Quackgrass with Roundup Ready-To-Use Weed & Grass Killer is the quickest approach to getting rid of it in your landscape and garden beds. Nevertheless, be ready: t It may take a second spray to entirely eradicate this plant because of its hardiness and extensive root system. 

Does pre-emergent work on quackgrass?

In lawns, quackgrass will start to generate new above-ground shoots during the end of summer and continue doing so throughout October. You can keep your lawn quackgrass free by using a pre-emergent herbicide at the beginning of the summer and then again in fall.

Is crabgrass good for anything?

Crabgrass is an excellent source of nutrition and one of the grasses that grow the quickest and can produce edible seeds in as little as six to eight weeks. It is suitable for poor soils where nothing else grows and does exceptionally well in well-watered lawns. However, it can also thrive in arid regions with poor soils as well.

Sources for Further Reading

Is It Crabgrass or Something Else? – College of Agriculture, Consumer, and Environmental Sciences, University of Illinois.

Quackgrass now appearing in turf – Michigan State University Extension

Quackgrass Identification and Control – College of Agriculture, Consumer, and Environmental Sciences, University of Illinois.

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Morgan Daniels

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