carpet grass guide

Ultimate Guide to Carpet Grass: What It Is & How To Grow It

In Grass Guides by Jamie

Do you have moist, sandy soil that’s difficult to grow grass on? Do you need a ground cover for a spot where low-maintenance is more important than appearance? While it won’t create an amazing-looking lawn, Carpet Grass (also known as Carpetgrass) comes in extremely handy for places where other grasses struggle.

What Is Carpet Grass (Axonopus affinis)?

Genus Axonopus affinis or A. compressus
USDA Zone 7 – 10 (Does best in Southeastern US)

Warm-season

Sun Full sun preferred; some shade tolerance
Soil Moist sandy soil; prefers wet and poorly drained soils
pH 5.0 – 7.0
Water Requirement Medium (Soil needs to stay consistently moist)
Nitrogen (lb/1,000 sq. ft.) 2 – 3 if frequently mowed (weekly)

0 – 1 if occasionally mowed

Growth Habit Stolons
Height Mow to 2 – 3 inches
Maintenance Low if no-mow or occasional mow

Medium if frequently mowed

Wear Medium
Tolerance High resistance to disease.

Medium resistance to insects.

Good tolerance of heat.

Low tolerance to salt and cold.

Germination Time 10 – 14 days

Fast Establishment

Appearance Light to medium green, coarse texture, distinct wavy leaf margin

Produces tall seed heads during the summer

What Is Carpet Grass

Carpet Grass is not a grass for everyone, but it is extremely useful in certain circumstances. If you live in the southeastern seaboard in the US and need a low-maintenance lawn for an overly wet soil that may have shade, then Carpet Grass can come to your rescue.

In many ways, Carpet Grass is the flip side of Centipede Grass. They both grow via stolons, are both fairly low maintenance, and can thrive in nutrient-poor, acidic soils, but while Centipede Grass prefers quickly drying sandy soils and suffers when sitting in wet soil, Carpet Grass prefers consistently moist or even wet soil. Meanwhile, if you struggle with salt-laced soil or water, you’ll want to turn to salt-tolerant Centipede Grass and avoid the salt-sensitive Carpet Grass.

While Carpet Grass will bounce back from fungal disease as soon as environmental conditions change, white grub and mole crickets pose a bigger threat. Both are easily treated with insecticides.

If you need an attractive turfgrass, give this grass a pass. Carpet Grass is coarse and, once established, can turn a lighter green. Like Bahia grass, it puts up large seed heads that look like whips during the summer heat. If you find them unattractive, you will need to mow more frequently, at least once a week or even every 5 days. The more you mow, the more fertilizer you need to give it (with occasional mowing, you may not need to fertilize at all).

It’s also very sensitive to the cold, so is slower to green up in the spring and goes dormant earlier in the fall.

But if your priority is low maintenance over looks, and you have the right conditions, then Carpet Grass is an excellent choice.

Pros and Cons of Carpet Grass

Pros Cons
Ideal for temperate regions with moist sandy soil (no salt). Unattractive grass with large whip-like seed heads.
The less you mow, the less fertilizer it requires. Few improved cultivars.
Thrives in acidic soil, so no lime needed. Low cold and salt tolerance.
Inexpensive to start a new lawn by seed. Prone to problems with white grub and mole crickets.
Grows into a thick mat that outcompetes weeds. It may get into your flower beds, but it’s easier to hand pull than Bermuda or Zoysia. Susceptible to common fungal diseases, but will recover quickly when environmental conditions change.
  Low drought-tolerance, likes soil to remain moist
  Slow to green up in the spring and quick to go dormant in the fall.

How To Grow Carpet Grass

Seeding/Overseeding

You can start Carpet Grass either by seed or sprigging (a piece of grass stem with roots and blades), but seeding is both easier and less expensive. Use two pounds of seed per 1,000 sq feet for a quick establishment, or 15 to 20 pounds per acre if you don’t need quick cover and you have a lot of ground to cover.

The best time to start a new Carpet Grass lawn is mid-April to May. The last date to seed is September 15. Carpet Grass gets established fast.

You don’t need to fertilize when starting a new Carpet Grass lawn, as this grass does well in low-fertility soils, but applying a light fertilizer with complete nutrients (1 pound of nitrogen per 1,000 sq ft) when preparing the soil can speed up establishment. Compost or an organic fertilizer like Milorganite is ideal for this purpose as it’ll keep feeding your lawn for months or even years.

Mowing

Mowing

How often you mow and to what height depends on the function of your lawn. If it’s in a highly visible area (like a front lawn), you may want to mow more often (as often as 5 – 7 days for seed heads) to a lower height (some experts even say you can go as low as ¾ inch, but most homeowners will want to stay at the safer and easier 1.5 to 2 inches), especially in the summer when it’s putting up seed heads.

If it’s in a less visible area, then mow less frequently to a higher height between 2 to 3 inches. Or even just let it grow natural. A rotary mower is better at cutting through seed heads when you mow less frequently.

Weeding

Grown in its ideal conditions (moist, acidic, low-nutrient sandy soil), Carpet Grass will grow thick enough to choke out even Bermuda. So long as you keep your grass healthy, it’ll grow into a thick sod, and you won’t need to worry about weeds. Perfect for a low-maintenance and out-of-the-way lawn.

Like Bermuda, Carpet Grass can spread into your garden beds or other lawns, but it’s much easier to dig out than Bermuda or Zoysia as it doesn’t have rhizomes. If your garden beds or other lawns dry out, then Carpet Grass will struggle to take hold.

Fertilizing 

How much you fertilize depends on how often you mow your grass. Carpet Grass does perfectly well in nutrient-poor soils, and so long as you mow infrequently, you may not need to apply any fertilizer. If you frequently mow, like in the summer, you will need to apply 2 applications per year (1 lb nitrogen per 1,000 sq ft per application) in late spring and early fall.

Test your soil at least once every 2 to 3 years, or if you’ve had deficiencies or excesses the year before, test your soil annually. Only fertilize as much as your grass needs. Carpet Grass outcompetes weeds and Bermuda grass because it doesn’t need a lot of nutrients to thrive. The more fertilizer you add only aids weeds.

If you’re growing Carpet Grass near or bordering waterways, be careful about what you add. Nitrogen and phosphorus are prone to run-off that cause toxic algae blooms. A natural fertilizer with low concentrations of nitrogen and phosphorus (or no phosphorus) prevents water pollution while giving your grass all the nutrients it needs.

Also check for state regulations as you may have particular restrictions.

Watering

Carpet Grass has low drought tolerance. This is a grass that loves to sit in moist soil. So long as your soil stays moist naturally, you won’t need to water. But you will need to water your lawn during dry periods.

Aerating

If you’re growing in sandy-type soils, you likely won’t have problems with compaction. With loam and especially clay soils, you may have more problems, especially with heavier foot traffic and use. Combine that foot traffic with the moist to wet soil that Carpet Grass loves, and you’ll have problems with compaction. Core aerate in the late spring to mid-summer when Carpet Grass is growing vigorously, so it can bounce back easily.

Dethatching 

Carpet Grass grows via stolons, which is one of the primary causes of thatch problems, but Carpet Grass itself isn’t known to be particularly prone to thatch problems. You’ll likely only have a lot of trouble if you’re feeding higher amounts of nitrogen, which forces growth. The more stolons that grow, the longer it takes the resulting thatch to decompose, the higher the thatch builds.

Keep an eye on thatch levels – if the thatch builds up over ½ inch, it’s time to dethatch. If you also need to aerate, then core aerate first as that process can remove thatch and may eliminate the problem without the need for dethatching.

Frequently Asked Questions

Is Carpet Grass The Same As St Augustine?

The problem with common names for plants is that the same common name can refer to two different plants. St Augustine (Stenotaphrum secundatum) is sometimes known as carpet grass or Carpet Grass, but there’s also another species of grass that’s always known as Carpet Grass (Axonopus affinis or A. compressus).

The two grass species can look fairly similar in appearance (except Carpet Grass has tall whip-like seed heads) and they both like sandy soil and shade, but St Augustine requires a lot of fertilizer and maintenance to grow a quality lawn while Carpet Grass can be truly low-maintenance in its ideal soil and grown as ground cover rather than a quality lawn.

Can You Mix Carpet Grass With Centipede Grass?

You can mix Carpet Grass and Centipede Grass, as their root structures won’t compete and they have similar needs (except for soil moisture levels). They’re sold together to serve as cover crops. But once established, the Carpet Grass turns lighter green and coarser, looking out of place and even weedy among Centipede. It also is slower to green up in the spring and faster to go dormant in the fall.

One species will become dominant depending on the soil moisture – if the soil remains moist, it’ll favor Carpet Grass, and if the soil dries out in between, it’ll favor Centipede. This creates a more resilient lawn – one will spread if moisture levels hurt the other. Not a problem if you need something where low maintenance and environmental resilience are more important than attractiveness, but you may wish to pick one if appearance does matter.

Is Carpet Grass A Weed?

Whether Carpet Grass is a weed depends on whether you were the one to plant it. If it shows up unexpectedly in your lawn, it’ll look out of place, and you should hand weed it. If your grass tolerates it (and your weather allows you to), letting the soil dry out between watering will keep Carpet Grass in check.

But Carpet Grass is a valuable turfgrass for providing cover and erosion control in places that have moist, acidic, sandy soil and also need minimal maintenance. These are places where it’s hard to grow other grass species.

About the Author

Jamie

Jamie is the founder of The Backyard Pros. When he was 15 years old he started working at a garden centre helping people buy plants, gardening products, and lawn care products. He has real estate experience and he is a home owner. Jamie loves backyard projects, refinishing furniture, and enjoys sharing his knowledge online.