Quackgrass vs Crabgrass

A piece of crabgrass against a white background.
What You'll Need
Organic compost
What You'll Need
Organic compost

Crabgrass is an extremely prolific weed that is often the bane of homeowners who strive for the perfect lawn. A close second to crabgrass in terms of weed problems is quackgrass. Recognizing the differences between these two kinds of weed can help you prevent and eliminate both types of unwanted lawn growth.


Crabgrass is an annual plant that grows every year from seeds sewn the previous year from plants that died over the winter months. It grows in mats and can be either large and grow as high as 3 feet, or small and have smooth blades that grow in clumps up to approximately 15 inches in height. Crabgrass spreads its green and sometimes purple tipped blades outward to create a crab-like appearance.

Because crabgrass has a very shallow root system, you may want to pull it out of the ground. However, if you do you may cause seeds to fall into the ground and germinate, allowing a new plant to spring up in its place next Spring.


Quackgrass, an aggressive perennial weed, has a deeper root system than crabgrass and reemerges every year. It reproduces from seeds and underground rhizomes.

TIP: Our expert gardening advisor, Susan Patterson adds, "Quackgrass was introduced from Europe about 200 years ago."

Quackgrass looks similar to crabgrass, but is more difficult to pull out because of its deeper root system, unless you are pulling out a seedling. The blades of quackgrass are long and tapered, and attached to hollow stems. Although quackgrass looks similar to crabgrass, and grows in clumps and mats, it is more upright than crabgrass.

TIP: Susan recommends, "Pull quackgrass out of flower beds as soon as you notice it to avoid it taking over the bed."

You need to be familiar with the root system of quackgrass to understand how difficult it can be to eradicate it from your lawn and garden. The roots are made up of rhizomes that spread outward to create new plants. Rather than simply eliminating the seeds, you also need to completely eliminate the root system. Otherwise, the plant will spring up again and again, no matter how many times you attempt to pull it up and remove it from the ground.

Eliminating Crabgrass and Quackgrass From Lawns

Crabgrass can be eliminated several ways. You can use an herbicide early in the season before the weed has the opportunity to establish itself in your lawn. You can also pour boiling water over it. This method will quickly kill the shallow roots, and soon the plant will blacken and die.

Quackgrass takes more effort to eliminate. In order to completely eradicate the weed, you need to use a non-specific herbicide that will kill not only the quack grass, but anything else that is growing around it.

TIP: Susan advises, "If quackgrass is severe in a flower bed you may have to pull out all of your plants and treat the area with a non-selective herbicide. Add organic compost and wait several weeks before re-planting."

For both crabgrass and quackgrass in lawns, using a pre-emergent herbicide before the spring warm-up will prevent new seedlings from germinating.

TIP: Susan suggests, "Check all plants that you buy before putting them in your yard to be sure that they do not have quackgrass growing with them."

The healthier your lawn is the less likely it is that quackgrass will take over. So, be sure to keep it in good health to avoid weeds overtaking it.