Home Blog Dallisgrass vs Crabgrass – differences

Dallisgrass vs Crabgrass – differences

by Jackson White

A beautiful green lawn is the pride and joy of every homeowner. This is only possible with frequent mowing, applying fertilizer, and occasional watering or yard aeration during spring or fall. Maintaining a lawn isn’t an easy task which also involves making sure that your lawn isn’t overrun by dallisgrass and crabgrass.

These are very common lawn weed grasses that that most people mistake one for the other. That’s why you must be able to identify the differences between the two weeds because you deal with each one in a very different way. You can prevent crabgrass with a pre-emergent because it’s an annual weed that sprouts from seed, but you can’t prevent dallisgrass, you can only deal with the individual plants as they appear on your lawn.


You can easily identify dallisgrass from its coarse texture with circular clumps that spread from short thick rhizomes. It has a grayish-green color with small hairs on the leaf collar and sometimes at the base of the leaf blade. This weed grows and spreads very fast in sandy or clay soils and is very hard to control because of its short rhizomes and it can grow back from its root system each year, unlike crabgrass that sprouts from seeds. This weed grass has very thick and stiff clumps that can be a tripping hazard when you’re walking across your lawn. Although this is an unwanted weed on your lawn, it’s a pasture grass for ranchers. However, its seed head to developing a fungus during summer which can be toxic to livestock.

Dallisgrass weed management

For you to prevent dallisgrass from taking over your lawn, you need to practice proper lawn maintenance, and since it’s hard to control it once it’s in your lawn, preventative measures are the best option.

Practice healthy lawn management

The first method in controlling dallisgrass is to maintain a healthy, dense turf by proper watering, fertilization, and mowing. Make sure you quickly fill all the bare spots with seed or sod and keep a thick, well-maintained lawn so there’s no room for the unwanted seed to germinate.

Use a pre-emergent method

The second method would be to use a pre-emergent herbicide that is toxic to both crabgrass and dallisgrass. Dallisgrass seeds are usually spread by wind, animals, and your lawnmower blades. These seeds have long spikes that grow several feet tall and each spike can produce 2-10 spikelets with each having two rows of seeds. The pre-emergent herbicide is absorbed into the soil so that the weed seeds that end up on your lawn die and don’t germinate. For the herbicide to be successful, it should be watered into the soil.

Use a post-emergent treatment

There are 3 ways this method can be effective. You can use an environmentally friendly method where you need to dig out all the unwanted weed, however, this method is labor-intensive. Alternatively, you can opt to use a post-emergent herbicide that you can apply several times with a 2-3 week interval to prevent regrowth. You can also use spot treatment using a non-selective herbicide if the weed grass has only affected a small section of your lawn, but it will also kill any plant it comes into contact with. Your turf will be killed along with the weed.


This is a weed that also grows in circular clumps, but unlike dallisgrass, it has a star-shaped pattern that grows outward and lies low to the ground. It spreads through new shoots of grass that grow from the center of the clump. This unwanted weed is an annual grassy weed that germinates during the late spring season and grows at the beginning of summer. It grows during the warm season which makes it difficult to control on your lawn. The two most prevalent types of crabgrass include the smooth crabgrass and large crabgrass that can grow from between 15-36 inches if not mowed. Its ability to thrive in poor soils and its fast and high growth makes it ideal as a summer forage grass for livestock and horses.

Crabgrass weed management

Keep a healthy lawn

The best way to prevent crabgrass seeds from germinating is to keep a healthy, lush, and thick lawn by deep and infrequent watering instead of sprinkling to avoid shallow roots that are vulnerable to crabgrass. Also, keep your lawn mowed no shorter than 2-3 inches.

Use a pre-emergent herbicide

This herbicide will prevent the germination of the weed seeds and root development. It will create a barrier in your lawn against any crabgrass seeds. Go for an herbicide that will control crabgrass and other broadleaf weeds, but be careful to first read the instructions before using it.

Use a post-emergent herbicide

If the crabgrass has already invaded your lawn, a selective or non-selective herbicide will be the best option. The selective herbicide will only target the specific weed, while non-selective will kill all plants including your lawn grass, and could be the best solution if your lawn is overrun by crabgrass.

Differences between dallisgrass and crabgrass


Dallisgrass is a perennial grass with a coarse texture that grows rapidly in a circular clump, but crabgrass is an annual grassy weed that also grows in a circular clump. Dallisgrass spreads using short thick rhizomes while crabgrass spreads through new grass shoots that grow a bit away from the center clump. You can identify dallisgrass from its grayish-green color with hairs at the leaf collar and base of the leaf blade. Crabgrass has a star-shaped pattern with thin blades that originate from the center.

Growth pattern

Both dallisgrass and crabgrass are invasive and troublesome weeds to eliminate or control once they invade your lawn. Both weed kinds of grass grow in circular clumps but unlike the dallisgrass, crabgrass grows outward in a star shape that is lower to the ground. As it continues to grow, it can become a raggedly star-shaped mat on your lawn. Dallisgrass clumps are stiffer and thicker and can trip you as you walk on your lawn.

How they spread

Dallisgrass spreads on your lawn with the help of short and thick rhizomes with a continuously growing underground stem that increases the diameter of the plant. It has lateral shoots and adventurous roots at intervals. It stores carbohydrates that perpetuate its growth and proliferation which makes it extremely difficult to control. Crabgrass, however, springs from seed and germinates during late spring and begins to grow in the summer before rapidly developing once the summer heat rises.

Types of weeds and how they spread

Weed type
How it spreads
Broadleaf perennial with long deep taproots
By seed and germinates all-year-round
Yellow nutsedge
Perennial sedge that forms dense colonies
By rhizomes and seed, but mostly by underground tubers
Broadleaf perennial with shallow fibrous roots
By small angular seeds
Perennial grass mostly active in cool spring and fall
By rhizomes and seeds, but usually by underground tubers
Broadleaf perennial with a fibrous and shallow taproot and expansive root system
By extensive roots, root and stem fragments, creeping stems, pointed seed capsules that disperse seeds, and extensive roots
Ground ivy
A mat-forming perennial broadleaf weed with a strong smell when crushed
By underground runners or stolons that root at the nodes and seed


Since it’s not easy to spot grass-like weeds such as dallisgrass and crabgrass in their early growth stages and it’s even more difficult to get rid of them once they develop on your lawn, the best way to prevent these weeds from taking over your lawn is to properly maintain your lawn and ensure your lawn is dense and thick with no bare spots.

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