Carex Is One of the Best Grass Alternatives for Your Lawn, Say Horticulturalists

Often referred to as sedge, carex is the sustainable grass alternative taking the landscaping world by storm. The reason why this genus of turf-like and often-native plants is gaining in popularity? A recent trial at Mt. Cuba Center, a botanical garden in Hockessin, Del., evaluated 70 types of carex and found that most make excellent native lawn replacements thanks to their spreading habits—many can even be mowed just like regular grass. We spoke with two garden experts to learn more about carex, including how to use it to transform your landscape. 

Why Carex Is an Exciting Lawn Alternative

Carex is a diverse group of blade-like plants that can create beautiful, low-maintenance, and eco-friendly lawns, says Lina Cowley, a garden and landscape expert with Trimmed Roots. Generally, they require less mowing, watering, and fertilization than traditional grasses, making them an excellent landscaping option for busy eco-conscious gardeners. "Many carex species are drought tolerant, which helps conserve water and makes them well-suited for regions that experience water scarcity," she says, adding that they're also shade tolerant—so they can thrive where other varieties of grasses just won't grow.

Most importantly, they're a sustainable addition to your landscape. "Carex plants provide habitat and food for pollinators and other beneficial insects, contributing to local biodiversity," says Cowley.

Choosing the Right Carex Species for Your Region

If you want to add carex to your yard, pick a species native to your zone—but be sure to consider its mow score before you use it as a lawn alternative. Per Mt. Cuba's report, the varieties that act most like traditional grass (and can be mowed for improved aesthetics and foot traffic) include Carex woodii (Wood's sedge), Carex eburnea (bristle-leaf sedge), Carex socialis (low woodland sedge), Carex pensylvanica (Pennsylvania sedge), and Carex jamesii (James' sedge).

Eastern and Central States

In eastern and central North America, Carex pensylvanica (also know as Pennsylvania sedge) is one of the best iterations to try, since it grows naturally in a range of weather conditions and thrives in a myriad of soil types, says Chris Young, a conservationist and the gardener behind Tiny Sur, a certified wildlife habitat garden in Los Angeles. This variety can also act as an accent or ground cover in moist woodland gardens and shaded perennial beds—and can grow to reach heights between six inches to 1 foot if left unmowed.

According to Mt. Cuba's report, Carex pensylvanica can be mowed easily (it has one of the highest mow scores) and thrives in both sunny and shaded environments.

Southern States

Those living in the South (or in drier parts of the east) should opt for Carex texensis (Texas sedge). As its name implies, "it is well-adapted to the hot and humid climates of the southern states," says Young.

Western States

"For the West, Carex tumulicola, commonly known as Berkeley sedge, is a great choice due to its ability to tolerate both dry and moist conditions—making it suitable for the varied climates of the western states," says Young. If you live in a place with more moderate weather, you can opt for some other prized species, like Carex praegracilis and Carex flacca, Cowley adds.

How to Convert to a Carex Lawn

If you're ready to take the leap and convert to a carex lawn, you'll need to do some prep work before you start planting.

Remove Grass

"Remove any existing grass, weeds, and debris from the area where you'll plant your carex lawn," Cowley says. You should amend your soil with organic matter to "improve its quality and drainage" when needed, she adds.

Prepare Soil and Seed

Next, prime the soil for seeds. "Loosen the soil with a rake or a tiller to a depth of about 2 to 4 inches," Young says. "Sow the carex seeds evenly over the prepared soil and lightly rake to cover them with a thin layer of soil."

Water the area thoroughly after seeding and keep the soil consistently moist until the carex is established, which should only take between two to four weeks, Young says. 

Using Plugs

If you're skipping seeds and using established plants (called plugs), follow instructions that are specific to the variety you've chosen. "Space the plants according to the species' requirements to ensure proper growth," says Cowley.

How to Care for Carex

Thanks to its low-maintenance nature, carex thrives on its own once established—there are just a few care suggestions to keep in mind.

Mowing

Most carex lawns require minimal mowing—some species only need one or two mowings per year. "If you prefer a more manicured look, you can mow your carex lawn more frequently at a higher mower setting," says Cowley.

Water and Fertilizer

Carex is drought tolerant once established, but it does benefit from the occasional deep watering during extended dry periods. When it comes to fertilizer, carex is low maintenance. "Carex lawns typically require little to no fertilization," Cowley says. "If you notice your lawn looking thin or lacking vigor, you can apply a slow-release organic fertilizer at a low rate to encourage growth."

Weeds

As for weeds? You should regularly inspect your lawn and remove any you find by hand (or with a spot treatment of herbicide). But pesky weeds should be few and far between: Many varieties (including the aformentioned Carex woodii) actually suppress weeds all on their own, the Mt. Cuba team shared in a press release. "By choosing a carex lawn, you'll enjoy a low-maintenance, eco-friendly alternative to traditional grass lawns while contributing to a healthier environment," Cowley says.