Most Common Grassy Weeds in Louisiana

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Louisiana is known for its lush landscapes and vibrant greenery. But maintaining a beautiful lawn can be a challenge, especially when it comes to grassy weeds.  As the name suggests, grassy weeds closely resemble regular, healthy turfgrass. Because of this resemblance, these pesky plants can quickly take over and ruin your yard's appearance. It can be difficult to differentiate between harmful grassy weeds and desirable healthy turfgrass. In this post, we'll explore some common grassy weeds in Louisiana and provide tips on how to keep your lawn weed-free.

Grassy weeds are known to be some of the toughest to control, so it’s essential to become as familiar with them as possible so you can get rid of them before they become a serious problem. Below is a list of Louisiana's most common grassy weeds and how to control and eliminate them.

Crabgrass

Crabgrass

Crabgrass, a common annual grass weed, can be spotted on lawns across the United States and is well known in Louisiana. As a warm-season grass, it germinates during spring and thrives throughout summer. This resilient weed is a rapid grower, capable of quickly asserting dominance over your lawn. Flourishing under warm, sun-soaked conditions and sandy soil, crabgrass is equally unfazed by drought and poor soil quality, making it difficult to eliminate once it is home in your lawn. Even though the annual weed dies off in the winter, each weed produces up to 100,000 seeds in its growth cycle, allowing more crabgrass to pop up once the warm season returns. Hand-pulling is an effective method of controlling these pesky weeds for small infestations, but for larger infestations, the right combination of herbicides that would eliminate crabgrass but not hurt desirable turfgrasses is needed.

Crabgrass resembles many turfgrasses, but these key differences will help you identify this pesky weed.

  • Leaves: The leaves of crabgrass are often a lighter shade of green than healthy turfgrass.
  • Growth: Crabgrass grows in clusters, forming a roundish shape, or V-shape with the leaves.
  • Stems: Stems are slender, with a reddish-purplish tint to them.
  • Roots: Roots are shallow and fibrous, able to spread quickly and take in the smallest of nutrients.
  • Flowers: Crabgrass flowers are small and inconspicuous, with tiny petals only showing up in the warm summer months.

Goosegrass

identifying goosegrass

Goosegrass is a warm-season annual grassy weed that is common in Louisiana. It is a prolific grower and can quickly take over a lawn, especially if the turf is thin or poorly maintained. Goosegrass prefers warm, moist soils and is often found in areas with compacted soil or poor drainage. It can also be found in lawns mowed too low or receiving too much foot traffic. It is a difficult weed to control, as it spreads quickly and easily, and large infestations can take years of regular care and maintenance to eradicate completely. Pre-emergent herbicides and post-emergent herbicides are the most effective treatment against these pesky weeds.

Goosegrass looks very similar to crabgrass, but there are key features that allow you to identify them correctly. Identification is important for the sake of using the right herbicides to get rid of this pesky weed.

  • Stems: Flat, creeping stems, light in color and turning white the closer it gets to the root.
  • Leaves: Folded or flattened leaves in various lengths up and down the stem.
  • Growth: Grows in a wagon-wheel-like rosette in the center of the plant.
  • Seeds: Silver-green feathery seed heads adorn the weed.

Sedges

nutsedge overhead

Sedges are not "true grasses" like most grassy weeds. They have solid, triangular stems and no nodes. Their flowers are also unique-looking and uncommon in grassy weeds. However, they are often referred to as grassy weeds because they grow in similar conditions and reproduce in similar ways.

Sedges thrive in poorly drained lawns and warm climates, meaning they are found all over Louisiana. They reproduce through seeds and rhizomes, which means they can quickly spread and take over your yard. They can also lie dormant in the soil, making it difficult to get rid of them completely. However, there are special herbicides that can be used to kill sedges.

To prevent sedges, make sure your lawn is well-fed and drains properly. Thick turfgrass will also deter their growth. Pre-emergent and post-emergent herbicides are the only ways to control these nuisance weeds. If you have a severe sedge infestation, you may need to hire a professional lawn care company to control it.

Here are some other ways to identify sedges:

  • Sedges have leaves that are typically shorter than the internodes (the spaces between the nodes).
  • Sedges have a sharp, triangular cross-section.
  • Sedges have a strong, unpleasant odor when crushed.

Types of sedges in Louisiana:

  • Yellow Nutsedge
  • Purple Nutsedge
  • Flatsedge
  • Hurricane Grass
  • Green Kyllinga

Annual Bluegrass

Annual bluegrass is a common lawn weed that is similar in appearance to Kentucky bluegrass and is found all over Louisiana. Annual bluegrass prefers moist soil and can tolerate shade. It is often found in lawns that are mowed too low, or that receive too much foot traffic. The plant will often die in the summer heat and leave bare spots all over your lawn.

Seeds germinate in late summer, grow throughout fall, and flower the following spring. To prevent the spread of annual bluegrass, it is best to apply a weed preventer in summer before the seeds begin to sprout and grow. While hand-pulling is effective for small infestations, large infestations require a combination of herbicides and often need the help of lawn care professionals to get rid of them completely.

Annual bluegrass is often difficult to identify in its early stages of development, but there are a few subtle differences that can help you tell it apart.

  • Leaves: Leave blades of annual bluegrass are lighter than those of kentucky bluegrass, with a canoe-shaped tip.
  • Seeds: Annual bluegrass produces fuzzy, white seed heads in the spring. These seed heads are a dead giveaway of the weed.
  • Growth: This pesky weed grows in clumps, while other grasses grow in a more uniform manner.