What Is Nutsedge?

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Sedge Grass Weeds


Here in Louisiana, we all want our lawns to be pristine and green, which is why it’s important to identify any troublesome plants that may sprout up. One of the most notorious lawn intruders in Louisiana is nutsedge. Unfortunately, Louisiana's climate produces the ideal conditions for nutsedge, which is why it's so important for homeowners to know how to stop it! In order for us to properly control this weed, we must first understand what it looks like and how it differs from grass or other types of weeds.

Identifying Nutsedge

identifying nutsedge

When it comes to the wide world of lawn weeds, nutsedge is truly unique. Nutsedge is a type of perennial, grass-like weed that is part of the Cyperaceae family (sedge family) of flowering monocots. "True sedges" refer to species within the Carex genus, but there are over 5,000 species of plants that are commonly referred to as "sedges." Nutsedge is a common lawn weed that belongs to the Cyperus genus within the sedge family, with roughly 700 different species considered a type of nutsedge.

As is the case with many grassy weeds, nutsedge leaves are almost indistinguishable from the grass in your lawn. Nutsedge is particularly aggressive and thrives in damp climates with excess moisture in the soil, making these plants very dangerous to our Louisiana lawns! An invasion in your lawn will quickly result in your turfgrass and other plants becoming dehydrated and thin, causing yellow patches to form in affected areas. However, unlike other grassy weeds, nutsedge is not technically a true grass, and there are some key differences you can look for that can help you identify nutsedge before it's too late!

What Does Nutsedge Look Like?

Nutsedge in lawn

Before nutsedge matures and flowers, it can be difficult to identify this weed because of its similarities to many grass species. In fact, nutsedge is commonly referred to as "nutgrass" or "watergrass" because it so closely resembles grass. When trying to spot nutsedge in your lawn, look for dense, scattered clump-type growth. If your lawn has been invaded by nutsedge, clumps of the weed will likely start to spread out across your lawn, and they will grow faster, taller, and greener than the healthy turfgrass in your lawn. Nutsedge is much easier to identify once the plant matures because of the thistle-like flower head developed by the weed, but this is a sign that a nutsedge invasion is already well underway.

The best way to identify nutsedge is not actually by sight! As a member of the sedge family, the stems of nutsedge feel different to the touch than those of grass species. The stems of sedges are solid rather than hollow, and they do not include nodes. The most easily identifiable difference is the triangular shape of sedge stems. If you are ever unsure whether you are seeing nutsedge among similar-looking grass, you can roll your fingers over the stem of the grass in question. If it is a nutsedge, you will feel three distinct edges that are not present on regular turfgrass.

What To Look For:

  • Taller, different-colored leaf blades than turfgrass
  • Leaf blades that are smoother and stiff
  • Dense clumps of growth scattered in your lawn
  • Triangular or V-shaped stems
  • Flowers in clusters at the end of a stem
  • Thistle-like seed heads in a spikelet formation

The Difference Between Yellow Nutsedge & Purple Nutsedge

nutsedge overhead

Though there are hundreds of different types of nutsedge plants, yellow nutsedge (Cyperus esculentus) and purple nutsedge (Cyperus rotundus) are the two species that you are most likely to see in Louisiana lawns. Both of these plants are perennial weeds, which means they will continue to be a problem for several seasons if you do not try to control them. As their names suggest, the most obvious difference between the two is the color of each weed's seed head, but other subtle differences can help you differentiate these two common weeds.

Yellow Nutsedge

  • Yellow/golden-brown seed head
  • Taller stems (up to 3 feet)
  • Light green leaf blades
  • Pointed tips of leaves
  • Leaves longer than stems
  • Spreads via tubers and seeds

Purple Nutsedge

  • Ruby/purple-brown seed head
  • Shorter stems (up to 2 feet)
  • Dark green leaf blades
  • Rounded tips of leaves
  • Leaves shorter than stems
  • Spreads via tubers (rarely seeds)

What Causes Nutsedge?

nutsedge seed head

Nutsedge thrives in warm weather and grows mostly in the heat of mid-summer. Most infamously, climates that often produce damp or wet conditions are breeding grounds for nutsedge due to the high moisture requirements of this weed. A lawn that has drainage issues will be more susceptible to a nutsedge infestation, as will a lawn that is frequently overwatered due to rainfall or improper lawn care. Garden beds with low-growing plants and flowers may also invite nutsedge growth because of the lack of shade coverage that would deter the nutsedge plants from thriving.

Common Causes:

  • Poorly draining soil
  • Overwatering
  • Excessive rainfall
  • Bare patches in your lawn
  • Mowing too low
  • Generally disturbed soil

The Spread Of Nutsedge

Once established, the roots of nutsedge are notoriously difficult to control or remove, as the root system is the primary way by which an invasion is spread. Nutsedge roots are known to go as deep as 4 feet into the soil, and they come in the form of complex tubers and rhizomes that spread out and invade the roots of your lawn or garden. These underground tubers and rhizomes sprout new shoots all over your lawn, even up to 10 feet away from the point of origin. Remember, yellow nutsedge weeds (and sometimes purple nutsedge) spread seeds in addition to sprouting new shoots, so you always have to be mindful of conditions that could invite nutsedge even if you don't see any nutsedge in your yard.

How To Control Nutsedge

Sprinkler System Installation

Nutsedge weeds are notoriously difficult to control, especially once they have already matured and started to spread. Unfortunately, typical weed control products are unable to control nutsedge; selective weed-killer treatments are not effective for pesky nutsedge weeds. There are certain mixtures and solutions that have been proven effective against nutsedge, but they must be applied properly, or your lawn could be severely damaged. Brothers Lawn Service always makes sure to take care of your nutsedge problem while still maintaining the general health of your lawn. While we encourage you to consider our weed control services in Louisiana, keep the following tips in mind when trying to control nutsedge weeds:

  • Avoid pulling-up roots. This activates the tubers and will sprout new shoots, especially if the weed has flowered.
  • Use herbicide on mature nutsedge. Look for halosulfuron- or sulfentrazone-based products.
  • Improve drainage. Aerating or installing a drainage system will decrease the amount of moisture in the soil.
  • Monitor sprinkler heads. Automatic irrigation systems can welcome nutsedge if they malfunction or have leaks.
  • Avoid mowing low. Mowing your lawn too low can cause bare batches to form, which will invite nutsedge.
  • Increase lawn density. Fertilize, seed, and make sure your lawn stays lush and robust to defend itself against the dreaded nutsedge!