How to Kill Bahiagrass

Co-authored by Maggie Moran and Sophia Latorre

Last Updated: March 29, 2019 References

Bahiagrass, also called highway grass, is often used for turfgrass or forage and can easily infiltrate your lawn, garden, or landscape plot as an undesirable weed. Bahiagrass is easily identifiable by its characteristic Y-shaped seed-head, and is present only in warmer climates. Although it will take time and persistence to remove bahiagrass, you can get rid of this pesky plant with the help of herbicides and regular lawn and garden maintenance.

Method 1

Method 1 of 2:

Removing Bahiagrass from Lawns

1
Apply a post-emergent herbicide in May. The first application of herbicide should take place when the bahiagrass is small and just beginning to grow. Choose a post-emergent herbicide to kill the actively-growing grass. Spray the herbicide on your lawn as per the package directions. Post-emergent herbicides are available at your local lawn and garden shop.^{[1]
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- Use metsulfuron to kill the bahiagrass without harming a bermudagrass lawn.
- Use metsulfuron, sethoxydim, or atrazine to kill the bahiagrass without harming a centipedegrass lawn.
- Use atrazine to kill the bahiagrass without harming a St. Augustinegrass lawn.
- Use imazaquin or metsulfuron to kill the bahiagrass without harming a zoysiagrass lawn.
2
Fill in bare spots with the desired turf. As the herbicide kills bahiagrass, bare patches will be left on your lawn. To ensure that these areas aren’t infiltrated with other weeds, promptly fill them in. Use plugs or sprigs of sod, rather than spreading seeds, for best results.^{[2]
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3
Reapply the herbicide after 4-6 weeks. To ensure that all the seeds, rhizomes, and plants are eradicated, you’ll need to apply the same herbicide again. Wait at least 4-6 weeks after the first treatment, then apply the herbicide to your entire lawn again as directed by the package instructions.^{[3]
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- The herbicide should not harm your existing grass or the new sod patches.
4
Mow the lawn frequently. It’s important to mow the lawn frequently to keep it healthy and prevent a re-emergence of bahiagrass.^{[4]
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Research source} Use a sharp mowing blade, as dull blades produce brown-edged grass. Keep bermudagrass and zoysiagrass at a height of 1 to 2 inches (2.5 to 5.1 cm), centipedegrass at a height of 1.5 to 2 inches (3.8 to 5.1 cm), and St. Augustinegrass at a height of 2.5 to 4 inches (6.4 to 10.2 cm).^{[5]
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- Don’t cut more than one-third of the grass height at a time, or the roots may stop growing. For instance, if you want to keep your grass at a height of 2 inches (5.1 cm), cut it when it reaches 3 inches (7.6 cm) tall.^{[6]
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5
Water the lawn only when it shows signs of water deficiency. Watering too often can cause bahiagrass and other weeds to flourish.^{[7]
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Research source} Wait until your lawn turns bluish-gray, holds footprints for more than a few minutes, or until the soil is dry and hard. Apply ¹⁄₂ inch (1.3 cm) of water to the entire lawn, then wait for it to dry out before watering again.^{[8]
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6
Fertilize the lawn once or twice per year. Regular lawn fertilization will prevent the bahiagrass from growing back.^{[9]
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Research source} Use a complete fertilizer, such as 12–4–8, 16–4–8, or 18-24-6, once or twice per year. You can do a home soil test to determine when your lawn needs to be fertilized.^{[10]
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- The numbers of the fertilizer refer to how much nitrogen, phosphorus, and potassium, respectively, it contains.

Method 2

Method 2 of 2:

Controlling Bahiagrass in Gardens and Landscape Beds

1
Pull bahiagrass by hand before tilling the garden. If you have a small garden plot or landscape bed, you can pull out the bahiagrass easily. Wait until after it rains or water the grass bed until the top 10 inches (25 cm) of soil are moist to make the bahiagrass roots easier to remove. Simply place your hand near the base of the bahiagrass and tug it out of the ground by hand.^{[11]
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- Do this before tilling the garden so as not to spread the seeds and rhizomes.
2
Lay down wet newspaper and 3 inches (7.6 cm) of mulch over the soil. Newspaper and mulch block the sunlight which would make seeds or rhizomes grow, making it an effective eradication technique. After pulling the visible bahiagrass, lay down 6-8 sheets of wet newspaper over your garden or landscape bed. Then, spread 3 inches (7.6 cm) of mulch, like grass clippings, pine needles, or compost, on top of the newspaper.^{[12]
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- The newspaper will decompose, so you don’t need to worry about removing them.
3
Apply glyphosate before planting for the season. At least 3 days before you plant flowers or vegetables, apply herbicide to the garden or bed to prevent bahiagrass from growing. Use a post-emergent herbicide like glyphosate. Refer to the herbicide package for application instructions.^{[13]
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- Glyphosate can be found at lawn and garden centers.
4
Use sethoxydim after planting. If you begin to see bahiagrass growing back after you’ve planted your flowers or vegetables, you can kill it with sethoxydim. Sethoxydim is a selective herbicide that will kill grass weeds without harming your plants and veggies. Apply it as directed on the package.^{[14]
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- Look for sethoxydim at your local lawn and garden shop.
- Don’t use sethoxydim if your garden or bed contains sweet corn.