Carpetgrass, a tough, mat-forming warm-season perennial grass, is sometimes used for lawn coverage in the Gulf states of the southeastern U.S. It is best suited for difficult sites where traditional grasses won't grow, such as boggy or shady areas, or areas with very poor soil. Although carpetgrasses don't produce a lush, thick lawn, they thrive in warm, shady, infertile environments that can be problematic for other grass species.
You'll need to be prepared, however, for them to turn brown more easily, look rather untidy with large seed stalks and heads, and create a more patchy lawn appearance. Because carpetgrass is so fast-growing, weekly mowing is essential during the summer season to keep your garden looking neat. Carpetgrass has a tendency to crowd out other species, so it can assume the role of a weed if it colonizes in an area where you are trying to get other grasses to grow.
Carpetgrass is normally sown by seed in the spring. It can spread quickly by creeping stolons, blanketing an area within a year or two.
|Common Name||Carpet grass, blanket grass|
|Botanical Name||Axonopus fissifolius, Axonopus compressus|
|Plant Type||Creeping perennial grass|
|Mature Size||1–12 in.|
|Soil Type||Moist, poor-to-average soil|
|Soil pH||Acidic to neutral (5.0 to 7.0)|
|Bloom Time||June to September|
|Flower Color||Yellowish-white (not showy)|
|Hardiness Zones||7–10 (USDA)|
|Native Area||Americas (tropical and subtropical regions)|
With enough moisture and warmth, carpetgrass is a very low-maintenance lawn grass option. It grows well in shady landscapes with infertile soils and on slopes. It requires frequent mowing to keep it looking neat, as this plant sends up new seed stalks every five days or so. But other than mowing, carpetgrass requires little care—even fertilizing is an optional step.
Carpetgrass is often selected for areas under thick tree coverage or in other shady positions. It grows well in partial shade and can still cope if it's planted in an area that is in full shade. It will also tolerate full sun, provided the soil is kept moist.
Carpetgrass prefers moist, ordinary soil and does fine in relatively infertile soils where other grasses struggle. It can cope with a variety of soil pH levels, though it prefers somewhat acidic conditions.
Moist (not wet) conditions are ideal for carpetgrass. In dryer soils and sunnier conditions, it will need regular watering. Narrowleaf carpetgrass is slightly more drought-tolerant than the broadleaf species, but it is still poorly suited for regions that experience regular drought unless watered regularly. However, carpetgrass doesn't like to be in standing water for prolonged periods, either.
Temperature and Humidity
Carpetgrass is native to the West Indies but has naturalized throughout the tropical and subtropical regions of the Americas. Its prevalence along the Gulf Coast gives you an indication of its preferred climate: warm and humid.
Of the two popular species, narrowleaf carpetgrass is a more frost-tolerant variety than its broadleaf relative, but it still won't appreciate freezing conditions, which can result in lawn burn. Preferable temperatures are between 60 to 80 degrees Fahrenheit during the growing season.
Given its ability to thrive in infertile soils, it shouldn't come as a surprise that carpetgrass doesn't need regular fertilization. However, if you want new grass to be established as quickly as possible, apply a light application of a balanced fertilizer to speed the process. Some gardeners also apply occasional applications of nitrogen fertilizer on carpetgrass that is being mown regularly.
Types of Carpetgrass
There are numerous species of carpetgrass, although there are only two varieties from the Axonopus genus that are commonly used for landscaping purposes.
- Broadleaf carpetgrass (Axonopus compressus) is a robust tropical species that grows well in hot, humid, wet, and shady areas. It's very fast-spreading and is considered to be a weedy, invasive species in many areas.
- Narrowleaf carpetgrass (Axonopus fissifolius) is generally considered a more favorable, attractive choice for use in temperate home garden landscapes. This species was previously known as Axonopus affinis before being renamed, and it's not uncommon to still see the old botanical name.
Narrowleaf carpet grass doesn't spread as aggressively as the broadleaf variety, but it's still prolific. You may have to fence off flower beds and paved areas to prevent the lawn from encroaching on these spaces.
Regular mowing of your carpetgrass during the warm months has two important advantages. First, it'll prevent your lawn from developing a disheveled appearance, as the seed heads are tall, unsightly, and quick to develop. Secondly, mowing before the seeds have a chance to appear will prevent the grass from spreading to unwanted areas.
During the growth season, new seed stalks will spring up as frequently as every five days. This means mowing every week is essential if you want to keep things in check. Carpetgrass can tolerate very close mowing (down to as short as 3/4 of an inch), but keeping it at a taller height of around 2 inches will produce the healthiest growth.
Carpetgrass can be propagated readily from the thin, rhizomatous roots. Here's how:
- During the warm growing season, dig up a small area of grass, roots and all.
- Shake off the loose soil, and tear the section into smaller pieces, each containing both roots and stems. There should be at least three or four rhizomes in each section.
- Replant the divisions, making sure to spread the roots out gently over the soil.
- Water well. The divisions need to be kept consistently moist until the roots are fully established; this usually occurs within two to three weeks.
Growing Carpetgrass From Seed
Growing carpetgrass from seeds isn't tricky. Wait until the warmer spring weather arrives. Tilling the soil so it is loose and smooth will help the seeds to sprout more quickly. After scattering seeds over the soil, rake lightly to ensure optimal soil coverage. The recommended application rate when using a broadcast spreader is about 2 pounds of seed per 1,000 square feet of lawn area.
The soil should be kept consistently moist for two weeks as the seeds germinate and sprout. During the next two months, weekly watering is recommended. Once the seedlings are established, unless the season is particularly dry, they should be fine left to spread with little attention.
Common Pests & Plant Diseases
Like many other grass species, carpetgrass can be susceptible to soilborne diseases such as brown patch and Pythium and to most leaf spot diseases, but the damage is usually not severe enough to warrant treatment with fungicide. You'll usually find that the grass recovers fine when conditions change. However, brown patch may persist for several months if it strikes in the fall.
Carpetgrass can be affected by white grubs, and in southeastern states, you may find that mole crickets cause damage. Both pests can be controlled with targeted pesticides.
How to Get Carpetgrass to Bloom
Carpetgrass does not have showy flowers, so there is no reason to encourage blossoming and seed heads. In fact, the normal recommendation is to mow very frequently so as to avoid the appearance of flower stalks and seed heads.
Common Problems With Carpetgrass
Carpetgrass is a largely trouble-free alternative for areas where more traditional turf grasses, such as bermudagrass, have trouble thriving. But there are a couple of common cultural complaints:
Invades Garden Areas
Carpetgrass will spread by stolons, so care should be taken to guard borders to prevent it from escaping into areas where it is not wanted. Your neighbors may not appreciate its colonizing tendencies.
More importantly, the grass should be mowed very frequently to prevent flower stalks and the subsequent seed heads from forming. An unkempt carpetgrass area can self-seed very freely and the seeds can spread great distances.
Lawn Is Weedy
Carpetgrass is better than many grasses at colonizing and squeezing out unwanted plants, but like any lawn, it can be subject to infiltration by some persistent weed species. Various broadleaf weedkillers and preemergent herbicides will work with carpetgrass lawns, just as they do with other turfgrasses. Where practical, spot treatment with spray herbicides is a better option than broadcast spraying.
Lawn Has Burned Patches
This is normally caused by unexpected periods of true frost, which can kill the tips of the grass plants. But unless the cold has been very deep and prolonged, the roots will normally recover and restore the lawn to full green.
What are the landscape uses for carpetgrass?
This is a good grass to use in shady or moist areas where more desirable grasses such as bermudagrass don't thrive. It can also be a good choice for shady, moist meadow or pasture areas. It responds well to heavy grazing by cattle, sheep, and other animals, for whom it provides adequate, though not exceptional, nutrition. But it is not well suited as hay grass for baling.
Carpetgrass can also make a good cover crop for areas where erosion protection is required.
How do I get rid of carpetgrass?
When carpetgrass gains a foothold in a lawn that consists primarily of bermudagrass or another recognized turf grass, it has a crabgrass-like appearance, and homeowners often view it as a weed. It has a lighter green color than surrounding grass, and will turn brown much more readily when conditions turn dry. Spot-treating it with a post-emergent herbicide such as Celsius WG is the best approach to eradicating carpetgrass. But be aware that the herbicides that kill carpetgrass will also kill centipede grass, so be precise about the application.