Identifying Crabgrass

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If you're seeing a lot of green in your lawn but not the kind of green you want, then you might have a crabgrass problem. Crabgrass can be very invasive and difficult to get rid of, and it will slowly take over your lawn. This pesky plant is one of the most easily identifiable weeds in the entire world, and this article will help you see less of them in your lawn!

What Is Crabgrass?

Crabgrass is an annual, grassy weed that belongs to the Digitaria genus of the grass family. It is characterized by its low-growing, spreading habit and its thick, wide leaves. Crabgrass typically grows in clumps or patches, making it quite unsightly when it invades a lawn full of normal turfgrass.

Crabgrass has notoriously shallow roots, meaning that this weed will steal nutrients and water away from your lawn before they can reach down to grass roots. Though it is not as aggressive as certain other types of weeds in Louisiana, it is dreaded by lawn care enthusiasts for its quick-spreading ability and its difficulty to control once it has established itself.

What Does Crabgrass Look Like?

crabgrass seedhead (1)

As a grassy weed, crabgrass looks and behaves very similarly to turfgrass. The biggest difference is that crabgrass grows in clumps or patches, while turfgrass grows in a more uniform way. Crabgrass also has wider leaves than most turfgrasses, and its blades are usually shorter. The tips of the blades are often pointy or blunt rather than rounded like those of most turfgrasses. Generally speaking, crabgrass leaves typically grow about 6 inches in length, with exceptions for certain species of the plant.

Another way to tell crabgrass apart from turfgrass is by its seedheads. Crabgrass produces seedheads that are long and thin, kind of like fingers. They can be anywhere from 6 to 24 inches long, and they often have a reddish color at the tips. These seedheads appear in late summer or early fall, and they're one of the ways that crabgrass spreads itself so quickly and easily.

In addition, you can also identify crabgrass by its roots. Crabgrass has shallow, fibrous roots that grow close to the surface of the soil. This is one of the reasons why it's so difficult to get rid of once it has taken root in your lawn.

It can be difficult to differentiate healthy turf from crabgrass, but an informed homeowner should be able to identify the difference. The following are some key identifiers to look out for when trying to identify crabgrass in your lawn:

  • Leaves from faint yellow to dark green.
  • Flat and wide leaves.
  • Long and thin stems.
  • Outward growth of immature leaves.
  • Upward growth of mature stems.
  • Growth is often described as a star pattern.

Types Of Crabgrass

crabgrass emerging

The descriptions of crabgrass noted above are general characteristics of the plant, but there are several different types of crabgrass that can be found in lawns across the country. The most notable and prevalent species are large or hairy crabgrass (Digitaria sanguinalis) and small or smooth crabgrass (Digitaria ischaemum).

  • Large Crabgrass: This variety is more common in the northern United States, while small crabgrass is more prevalent in the South. Its leaves tend to grow longer than those of small crabgrass. Large crabgrass is also called hairy crabgrass because the plant is covered in tiny hairs. The leaves of large crabgrass are also wider than the leaves of small crabgrass.

  • Small Crabgrass: As you can probably guess, this species develops smaller leaves and grows lower to the ground than large crabgrass. This weed is also referred to as smooth crabgrass because the sheath and leaves of this species does not have any hairs, unlike large or hairy crabgrass. You may also be able to identify small crabgrass by a faintly red stem that is observable when viewed from above. Small crabgrass is the most common species in the United States.

Where & When Does Crabgrass Grow?

Dry Compressed Soil (2)

Crabgrass is a warm-season weed, which means that it thrives in hot, dry conditions. It loves full sun and can tolerate (and even prefers) poor soil conditions. In fact, crabgrass is often one of the first weeds to appear in a lawn that is stressed by drought or other environmental factors. Crabgrass will also happily grow in areas of your lawn that are compacted or have poor drainage.

Crabgrass is most active during the summer months, when temperatures are warm and conditions are dry. However, it can germinate and begin growing at any time during the year if conditions are right. In Louisiana, crabgrass has been known to germinate as early as February. In northern states, crabgrass may not appear until June or July. In general, crabgrass begins germination when soil temperatures reach 60 degrees Fahrenheit.

How Does Crabgrass Spread?

crabgrass bunch growth (1)

Once crabgrass takes hold in your lawn, it is difficult to get rid of. The plant can produce up to 150,000 seeds per season, which means that a single crabgrass plant can quickly turn into a full-blown infestation. Crabgrass also has shallow and fibrous roots that make it difficult to pull out of the ground without leaving some of the roots behind, and the plant often grows back quickly after being removed.

In addition, crabgrass seeds can remain dormant in the soil for several years before germinating. This means that even if you're able to get rid of all the crabgrass plants in your lawn today, there's a good chance that the weed will come back next year or even several years from now.

How To Remove & Prevent Crabgrass

Brothers Lawn Care Mowing

The best way to prevent crabgrass is to have a healthy, thick lawn that crowds out the weed before it has a chance to take root, which makes proper mowing and watering habits the first lines of defense. Once crabgrass emerges in your lawn and throughout your yard, it can be difficult to remove. If you do start to notice crabgrass in your lawn, the best way to get rid of crabgrass is to pull it up by the roots, but this can be a challenging task given the plant's root system.

If you have a small patch of crabgrass, you may be able to remove it by hand. Use a weeding tool or your fingers to loosen the soil around the plant and then pull it out of the ground, being careful not to leave any pieces of the root behind. You can also use a lawn edger or power trimmer to cut away at the crabgrass plants and prevent them from spreading.

For larger areas of crabgrass, you may need to treat your lawn with herbicides. Larger infestations will have more complex root systems, which make it more likely that pulling will be ineffective. Be sure to carefully read and follow all instructions on the label before using any type of chemical product in your yard. Below are just a few tips on how to deal with crabgrass:

  • Apply liquid pre-emergent designed for crabgrass.
  • Overseed/fill bare patches in your lawn.
  • Keep grass 3 inches or taller.
  • Water deeply and infrequently.
  • Remove emerged crabgrass before it sets seeds.
  • Dig out all the clumps of leaves and roots as weed emerges.

Of course, the very best protection from crabgrass comes from professional lawn care. Regular and proper mowing, fertilizing, and watering, among other services, will keep your Louisiana lawn free from crabgrass all year long. Call Brothers Lawn Care today to start defending your turf!