Carpetgrass is a common grass in Louisiana and other Gulf Coast states where wet, infertile soils make other species of grass hard to grow. Also called “petit gazon,” carpetgrass has moderate shade tolerance and crowds out most weeds once established. For homeowners who have given up on more common species of turfgrass in their lawn, carpetgrass is a viable solution for a low-maintenance lawn on a challenging piece of land.
Carpetgrass at a glance
Classification: Warm-season grass
Spreads by: Stolons
Shade tolerance: Moderate, but not as high as St. Augustinegrass
Drought resistance: Moderate, but won’t survive in dry conditions (shallow roots)
Foot traffic tolerance: Low to moderate
Maintenance needs: Mow weekly to control tall seed heads
Mowing height: 1-2 inches
Potential for disease: Large patch is common
Soil pH: 5-6
Soil type: Infertile, moist but not waterlogged, acidic, sandy
Other notes: Usually established by seed. Flourishes in warm and humid conditions along the Gulf Coast. Does not thrive in arid climates. Not salt tolerant.
What is carpetgrass?
Common carpetgrass (Axonopus affinis), also called Louisiana grass, is a common turfgrass found along the Gulf Coast where other turfgrasses will not grow. It tolerates high humidity, infertile soil, high rainfall, and high soil moisture. You can find this grass in Zones 8 and up in coastal regions from the Carolinas to East Texas and Hawaii.
Although carpetgrass is a useful lawn grass in hard-to-grow areas, it is considered a weed in lawns with other grasses. In addition to lawn use, carpetgrass is used as a roadside grass, pasture grass, or nurse grass in centipede lawns. (Note: A nurse grass is a grass that is planted with another species because it germinates faster and, once the primary grass establishes itself, dies away.)
This versatile grass prefers a soil pH of 5-6 but can grow in soils with a pH from 4-7. (You may want to add lime or a soil acidifier if it is below 5 or above 6.) Carpetgrass is inexpensive to start from seed and needs no fertility to grow. For this reason, it often pops up in lawns with other grass types that have low-fertility soils.
Pros and cons of carpetgrass
Since carpetgrass has specific growing conditions and maintenance needs, you want to make sure it is right for you.
Pros
✓ Low growing and low maintenance
✓ Ideal grass for infertile, acidic, moist soils
✓ Low or no fertilizer required
✓ Available as seed or sprigs
✓ Can be used as a nurse grass in a centipede lawn
✓ Ideal for hard-to-grow areas
✓ Grown in Zones 8 and warmer
Cons
✗ Must mow every week during the growing season to control seed heads
✗ Not salt tolerant
✗ Does not thrive in arid regions
✗ Must be watered regularly during dry periods
✗ May develop excessive thatch if highly managed
✗ Does not produce a “showcase” lawn
✗ Goes dormant quickly once cooler fall temps hit and slow to green up in spring
How to establish carpetgrass
As with all warm-season grasses, plan to seed carpetgrass from late spring to early summer. A grass drill will make quick work of this project, so look for one at your local machine rental store. Or, use a spreader and go back over the lawn with a rake to cover the seed.
Water the soil so that it stays moist for about the next two weeks. Then, continue to keep the soil moist until the lawn has established, which is usually eight to 10 weeks after you plant. Fertilize at 1 pound of nitrogen per 1,000 square feet when you seed and once per month until the lawn is established.
How much does carpetgrass cost?
Carpetgrass is most commonly available as seed. In big box stores, you may find a carpetgrass/centipedegrass mix, since these two grasses are similar in appearance and are often planted together.
Carpetgrass seed: Starts at around $16-$22 for a one-pound bag. However, the price per pound drops as you buy in greater quantities per bag.
Caring for carpetgrass
Yearly carpetgrass maintenance is significantly less than for other warm-season grass types.
Mowing
Mow at least once per week at 1 to 2 inches to control seed heads during the growing season.
Water
One inch of water per week is ideal for carpetgrass lawns. If you don’t get this naturally via rainfall, plan to turn on the faucet and give the lawn a drink. Water sandy soils about twice per week at ½ inch each time. Soils with less sand benefit from the “deep but infrequent” watering approach. Remember to water no later than 10 a.m. to discourage fungus growth.
Fertilization
Fertilization is optional. If you wish to fertilize the lawn, use ½ pound of nitrogen per 1,000 square feet per application and up to 2 pounds per year.
Dethatching and aeration
Excessive thatch may occur, but only if there is too much water or fertilizer applied. Rent or buy a dethatching machine once the levels reach or exceed ½ inch. Plan to dethatch a few weeks after the lawn greens up in spring, and space the blades at 2 to 3 inches wide and about ¼ inch deep. Blades that are spaced too closely will cause damage to the turf.
A core aeration machine also will remove some thatch as it pulls plugs of soil from the grass. This is most often used on compacted soils, so if your soils aren’t compacted, it’s probably not a necessary lawn chore.
Note: Thatch is a layer of undigested plant matter that lives between the grass and the soil. A little is okay, but too much prevents water and air from reaching the soil.
Disease, insects, and weeds
Disease: Large patch is a common fungal disease on carpetgrass lawns. Apply fungicide preventatively if you’ve had problems in past years. Large patch is not likely to cause long-term damage.
Insects: White grubs and nematodes are sometimes a problem in carpetgrass lawns.
Weeds: Not many weed problems. This grass fills in well and out-competes most weeds. If you need to manage weeds that come up, consider organic options or hand-pulling. There aren’t many herbicides that are suited for carpetgrass.
Some information taken from Fundamentals of Turfgrass Management, 5th ed. by Christians, Patton, and Law
If you think a carpetgrass lawn may be right up your alley, contact one of our local lawn care professionals. They can help you select, install, and care for your grass so you can spend your free time doing what matters most.
Main Photo Credit: Forest and Kim Starr | Flickr | CC BY-SA 2.0
