Carpetgrass spreads aggressively in moist, acidic, low-fertility soil. In many yards, carpetgrass shows up alongside bigger issues like thin turf and soil imbalance. Fixing those underlying problems is key to long-term control.
This guide will help you identify this weed, kill it, and keep it from coming back.
Getting rid of carpetgrass takes the right timing, the right products, and consistent follow-through. LawnStarter’s lawn treatment services can handle the process for you.
| Key Takeaways |
|---|
| • Carpetgrass thrives in moist, low-fertility, acidic soil. Fixing those conditions is one of the most effective long-term controls. • Chemical post-emergent herbicides like Celsius WG are the most reliable option for serious infestations, but always check the label to confirm carpetgrass is listed. • Maintaining a thick, healthy lawn is your best defense against carpetgrass returning after treatment. |
How to Identify Carpetgrass
Make sure carpetgrass is the weed in your lawn before treating it. Treating the wrong weed wastes time, money, and product.
Grassy weeds require different herbicides than broadleaf weeds, so a correct ID before you buy anything could save you from a frustrating and costly mistake.
There are 2 types of carpetgrass that look slightly different:
| Type | Leaf Width | Heights |
| Narrowleaf carpetgrass (Axonopus affinis or Axonopus fissifolius) | Narrow blades (1/16–1/4 inch wide) | Grows 10 to 30 inches tall |
| Broadleaf carpetgrass (Axonopus compressus) | Wider blades (1/6–3/8 inch wide) | Grows up to 6 inches tall |
Source: University of Hawaii at Manoa
Do not confuse broadleaf carpetgrass with broadleaf weeds in general. Both types listed above are grassy weeds.
Use these identifying features to tell carpetgrass apart from other grassy weeds:
Growth pattern: Dense, carpet-like mat that spreads aggressively
Seed stalks: Y-shaped seed heads up to 12 inches tall in summer, sometimes with a third seed head below the Y
Blade tips: Distinctive boat-shaped appearance
Grass sheath: Open sheath with hairs along the edge
How Carpetgrass Differs from Similar Grassy Weeds
Carpetgrass is most often confused with 2 other grasses: centipedegrass (a desirable lawn grass in the South) and crabgrass (a weed). Getting this wrong means treating for the wrong plant, so here is a quick way to tell them apart:
Carpetgrass vs. centipedegrass: These 2 look nearly identical at ground level. The telltale difference: Carpetgrass sends up tall, Y-shaped seed stalks (2-3 spikes) in summer. Centipedegrass produces only a single, unbranched seed spike that stays low and inconspicuous.
Carpetgrass vs. crabgrass: Crabgrass sprouts in a star-like pattern from a central point and tends to appear earlier in spring. Carpetgrass grows in a dense mat and emerges later when temperatures are consistently warm.
See Related:
7 Ways to Get Rid of Carpetgrass: From DIY Fixes to Chemical Treatments
Carpetgrass is a perennial weed. It comes back year after year, unlike annual weeds that die after one season. It goes dormant in winter but fully regrows from the roots each spring unless you eliminate it completely.
Here are 7 methods to control carpetgrass. Start with the cultural fixes (methods 1–3) if your infestation is mild or you prefer to avoid chemicals. Jump to method 7 if carpetgrass has already taken over a significant portion of your lawn.
| Method | Best For |
| Withhold water | Drought-tolerant grass |
| Fertilize soil | Low-fertility soil |
| Raise soil pH | Acidic soil (pH 5 to 6) |
| Spot treat with salt (sodium chloride) | Isolated areas only |
| Spot treat with vinegar | Isolated areas only |
| Spot treat with baking soda | Isolated areas only |
| Use chemical herbicides | Serious infestations |
1. Withhold Water to Dry Out Carpetgrass
Carpetgrass loves moist soil, so one of the easiest methods is to stop watering wherever you see it growing. Once the weeds die and turn brown, rake them out.
This approach works only if you have a drought-tolerant grass type such as Bermudagrass, bahiagrass, or Zoysiagrass.
See Related: 10 Best Drought-Tolerant Grasses for Your Yard
2. Fertilize Your Lawn to Smother Carpetgrass
Here is a counterintuitive one: Carpetgrass thrives in low-fertility soil, so it actually has an advantage when your lawn lacks nutrients. Feed your lawn the nutrients it is missing, and you tip the scales.
A well-fed lawn grows thicker, which decreases colonization of most weeds. Just be careful not to overdo it. An over-fertilized lawn can cause more problems than it solves.
Before adding anything, test the soil through your local university extension program to find out which nutrients it’s missing.
See Related: 9 Reasons Why Soil Testing Is Important for the Lawn
3. Raise Your Soil’s pH to Get Rid of Carpetgrass
Your soil test will also reveal your soil’s pH and whether your lawn needs lime. An acidic soil pH between 5 to 6 suits carpetgrass, but most lawns perform better when soil pH is between 6 to 7.
If the soil pH is lower than your turfgrass needs to thrive, all you need to do is work a soil amendment called agricultural lime into your topsoil. You can purchase it (sometimes called “gardening lime” or just “lime”) at most garden supply centers or online.
Apply the lime application rate recommended by your soil test (never more than 50 pounds per 1,000 square feet in a single application).
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4. Spot-Treat Carpetgrass with Saltwater
Salt draws water from plants’ leaves, stems, and roots, leading them to wilt, brown, and die. It can damage carpetgrass and many other weeds, as well as desirable plants. Experts don’t encourage it since applying salt too often or too much can harm the soil.
Warning: Only use this method on isolated spots like yard corners or carpetgrass in pavement cracks. Don’t apply in your lawn, flower beds, or near shrubs and trees.
Make a solution with water and salt, add it to a watering can and pour the saltwater directly over the spots where carpetgrass has taken over. Apply when no rain is forecast for at least 3 days so the salt is not washed away.
See Related: Signs of Salt Damage on Your Lawn and Why They Happen
5. Douse Carpetgrass with Vinegar (Carefully)
Vinegar is one of the most common alternatives to chemical herbicides, and it damages pretty much any weed, including carpetgrass. It’s more effective on broadleaf weeds, but can also burn the leaves of carpetgrass and damage it severely if you apply it at the right time.
According to the University of Maryland, vinegar with 5% to 10% acetic acid vinegar (5% is your regular kitchen vinegar) works for weed seedlings with 1 or 2 leaves. If carpetgrass already has 3 to 4 leaves, use industrial vinegar with 20% acetic acid.
It doesn’t kill the roots, so you’ll need to apply it several times to keep the plant from regrowing. Leave at least 2 weeks between applications, and always wear personal protective equipment.
Pro Tip: Adding yucca extract helps the herbicide stick better to the leaves and do more damage.
WARNING: Vinegar kills all plants, not just weeds. Do not pour vinegar on your lawn or other plants you want to keep alive. Vinegar is best for carpetgrass in isolated areas, like the cracks in your driveway.
See Related: Does Vinegar Kill Weeds?
6. Sprinkle Baking Soda on Carpetgrass
Baking soda (sodium bicarbonate) works as a non-selective desiccant: its sodium content draws moisture out of plant tissue, which can stress or damage whatever it touches. It is most useful as a spot treatment on isolated patches, not as a lawn-wide carpetgrass killer.
To try it, lightly wet the carpetgrass so granules stick to the blades, then sprinkle baking soda directly on the weeds. Reapply every few weeks if the carpetgrass recovers.
WARNING: Baking soda does not distinguish between carpetgrass and the grass you want to keep, so any amount strong enough to harm carpetgrass can also injure your desirable turf.
Sodium also builds up in the soil rather than breaking down, which can degrade soil structure over time. Reserve this method for areas where you are not worried about the surrounding lawn, such as cracks, edges, or patches you plan to replant.
7. Use Chemical Herbicides on Carpetgrass
When gentler methods fail, chemical herbicides are the most potent option. Look for a post-emergent herbicide that lists carpetgrass or grassy weeds on its label.
For best results with weed spraying, apply when carpetgrass is actively growing, typically late spring through summer, and avoid spraying when the grass is stressed by drought.
Herbicides that kill carpetgrass include:
Celsius WG: A selective herbicide that controls carpetgrass while staying safe on Bermudagrass, centipedegrass, St. Augustinegrass, Zoysiagrass, and buffalograss. Do not use it on bahiagrass, seashore paspalum, or cool-season lawns such as tall fescue and Kentucky bluegrass.
Finale XL T&O: A non-selective, contact herbicide that kills all green vegetation it touches, including your lawn. Reserve it for spot treatments and edging in areas you plan to clear or replant.
Always check the product label before purchasing to confirm carpetgrass is on the list of weeds controlled. Note that some chemicals may require a license for use in some states. For application instructions and frequency, follow the label on the specific product you buy.
See Related: Glyphosate: Pros, Cons, and Alternatives
Home Remedies Worth a Second Thought
Borax relies on boron toxicity to injure plants, which is unreliable and can leave boron in the soil. Boron doesn’t break down like regular weed killers; where it accumulates after repeated applications it can lead to bare areas where no vegetation will grow.
Arm and Hammer detergent is mostly surfactants and sodium salts, not a tested herbicide. It may damage plants if used in enough amount, but it’s not selective. It will damage all plants and also harm the soil.
How to Prevent Carpetgrass
The best defense against carpetgrass is to thicken your lawn. Dense turf simply leaves no room for it to establish.
Once you have killed the carpetgrass, you will likely have bare patches. Overseed those areas right away with your lawn’s grass type to prevent carpetgrass or other weeds from returning.
To keep your lawn healthy so it resists the invasion of carpetgrass:
Don’t over-water. Only water when your grass shows signs of drought stress, such as fading color or leaf curling. Watering too frequently leads to overly moist soil, which leads to carpetgrass.
Mow to the right height. Each type of grass has specific mowing requirements to keep it as healthy and thick as possible. Know your grass type and adjust your mower height accordingly.
Fertilize on the right schedule. Research your grass type to find out how many fertilizer applications it needs each year to grow its best.
Improve soil drainage by aerating the lawn or adding compost. If your soil has poor drainage, your lawn’s roots will become weak, which will lead to weaker grass in general. Plus, poor drainage means wet soil, which is a breeding ground for carpetgrass.
In flower beds and gardens, use mulch as a physical barrier. It blocks weeds and benefits your plants in other ways too.
If you have had problems with carpetgrass before, apply a pre-emergent herbicide in early spring before carpetgrass’s growing season. Look for pre-emergents labeled for use on carpetgrass.
See Related: Summer Lawn Care Guide
FAQs
Carpetgrass thrives in soil that is overly wet, acidic, and low in nutrients. It is especially persistent in Southern lawns, where warm, humid weather and wet soils create the perfect environment for it to spread.
Yes, carpetgrass has very poor cold tolerance and is often the first grass to turn brown in fall and the last to green up in spring.
Yes, in some areas it is intentionally grown as a low-maintenance turfgrass, especially in the Deep South where soils may be acidic and fertility is low. The tradeoff is appearance and performance: it can look patchy in cool weather, and it does not tolerate heavy traffic.
It can. Carpetgrass spreads by above-ground stolons, so it may creep across property lines, especially into thin, moist turf. Edging can slow but not always stop it. If both yards are affected, coordinated treatment is worth discussing.
Let LawnStarter Handle Your Carpetgrass Problem
Killing carpetgrass without harming your lawn takes time, the right products, and the right timing. Miss any one of those, and you are treating the same lawn again next season.
If you would rather make sure you’re getting this weed under control, LawnStarter connects you with local, vetted pros who know exactly when and how to eliminate carpetgrass for good with lawn treatment services.
Get an instant price from LawnStarter and get your weekends back.
Main Image: Carpetgrass invading lawn before removal treatment. Image Credit: Harry Rose / Flickr / CC BY 2.0
