Getting in the green zone

By Stacie Zinn Roberts

Give your clients the green lawns they desire by understanding the proper grasses for the job.

Marc Marsh’s phone rings as he looks out over acres of deep green zoysia and Bermuda grass growing at his sod farm in Cheraw, South Carolina. On the phone is a local landscape contractor calling to ask Marsh’s advice about which grass variety to plant in a client’s large landscape project. As president of Turf Connections, Marsh operates four such farms in North and South Carolina, and he takes calls like this on a daily basis.

“Where is the job located?” Marsh asks the caller and with good reason.

Grass selection, just as in real estate, boils down to, “location, location, location.” It is the first and most important factor to consider.

Just as palm trees thrive in warmer climates and fir trees love cooler zones, turfgrass species, too, are divided into cool-season and warm-season categories. Once you know which “season” the location you’ll be planting lies in, you’ll be halfway home.

Other than that, the difference between them is that cool-season grasses are predominantly grown from seed, and warm-season grasses are predominantly grown from sprigs. Both cool-season and warm-season grasses are available as sod.

According to The Lawn Institute, East Dundee, Illinois, cool-season turfgrasses are those species with optimum growth at temperatures between 60 and 75 degrees Fahrenheit. Common cool-season grass species for lawns include tall fescue, Kentucky bluegrass and rye grass. Cool-season grasses grow well in the upper two-thirds of the United States, in places like Washington state, Minnesota and Massachusetts.

Warm-season turfgrasses are those species with optimum growth at temperatures between 80 and 95 degrees Fahrenheit; you’ll find them growing in the southern states. Common warm-season grass species for lawns include bahia, Bermuda, centipede, St. Augustine and zoysia.

Each species has its distinctive aesthetics, characteristics and benefits.

The tricky transition zone

Turf Connections’ two North Carolina sod farms are in the “transition zone,” the middle region of the country that straddles the dividing line between climate zones, where both cool- and warm-season grasses are planted. At those two farms, Marsh grows tall fescue because that’s what is mainly preferred in Charlotte and the surrounding metropolitan area. In Greenville, South Carolina, less than two hours south of Charlotte, Bermuda and zoysia are preferred.

Planting turf in the transition zone is a bit more complicated. If both cool- and warm-season grasses will work, how do you choose which one to plant? In those cases, Marsh says regional preferences, microclimates or other factors must also come into play.

Homeowners associations will often have rules specifying which grass species they want planted on their properties; check with them before sodding or seeding. “Some HOAs require fescue or Bermuda or zoysia,” says Marsh. “Others will let you plant anything you’d like.”

Just because a grass will survive in a region doesn’t necessarily make it the best choice, however. Other factors such as soil type or intended use should be taken into consideration too. While fescue will grow just fine in clay soil, it’s not an ideal growing medium for zoysia. If grass is going to be planted on a sports field or high-foot-traffic area in a cool-season zone, a wear-tolerant grass should be chosen, such as Kentucky bluegrass; if that high-traffic area is in a warm-season or transition zone, a Bermuda grass would work better. If drought is an issue in a cool-season area, fescue is a good choice; in warm-season drought-prone areas, pick Bermuda or zoysia.

Species and cultivars

Clouding the issue further is the fact that not all zoysias, bluegrasses or Bermudas are created equal. Even within specific grass species, characteristics vary by which variety (also called a cultivar) of that species we’re talking about. These cultivars are bred to bring out beneficial characteristics such as drought, shade or cold tolerance; low need for maintenance; color and texture or early spring green-up.

For instance, Tahoma 31 Bermuda grass is a new cultivar developed by turfgrass breeders at Oklahoma State University, available through more than a dozen sod farms in the United States. An exceptionally cold-tolerant grass, Tahoma 31 will grow in warm-season climates, through the transition zone and into what is commonly considered cool-season territory as far north as Pennsylvania and Indiana.

In a five-year research study conducted by the National Turfgrass Evaluation Program, Tahoma 31 was compared to more than a dozen other Bermuda

grasses for specific beneficial traits. It ranked first in spring green-up and winter survivability and tied for first place in turfgrass quality. The grass also received high ratings for drought tolerance, leaf texture, color and vigor. Studies conducted by turfgrass scientists at Texas A&M University and Oklahoma State University showed that Tahoma 31 used 18 percent less water than its closest competitor, a grass developed at the University of Georgia called TifTuf.

The point is, for a professional landscaper trying to decide which grass to plant, making a selection by species alone does not go deep enough. Differences among varieties within a species, such as cold tolerance or thirstiness, can be dramatic and can seriously impact the success or failure of a landscape project.

Cool-season lawn grasses

Tall fescue: Tolerant to heat and drought, low maintenance, deep roots, medium-bladed texture

Kentucky bluegrass: Excellent winter hardiness, susceptible to heat and drought, medium-to-fine texture, soft underfoot

Rye grass: Quick to establish, fine-bladed texture, shallow roots


Warm-season lawn grasses

Bahia grass: Has an open canopy, drought tolerant, medium-bladed texture, susceptible to weeds

Bermuda grass: Wear tolerant, finely textured, forms dense canopy

Centipede grass: Drought tolerant, medium-bladed, lime green color

Seashore Paspalum: Salt tolerant, fine leaf texture, higher maintenance

St. Augustine: Wide-bladed, thick thatch layer

Zoysia grass: Excellent shade tolerance, low maintenance, medium-to-fine blades


Blended families

While warm-season grasses are generally sold as monocultures (one species alone), there are also seed blends and sod grown from seed blends that combine several cultivars of a species selected for their differing characteristics in order to create a better, hardier stand of grass.

Nathan Cox is president of Desert Green Turf, Moses Lake, Washington, a 550-acre farm where sod is grown for the landscape market from cool-season bluegrass, rye and fescue blends. For large projects, Cox will custom-blend and grow sod to order.

His bluegrass blend includes four varieties of bluegrass and two varieties of rye. The four bluegrasses have different desirable traits, and the rye was added for its quick germination. The combination, Cox says, makes for a stronger sod overall that will adapt to the local microclimate, allowing the seed variety that adapts best to eventually become dominant and take over.

Another consideration when selecting a grass, Marsh says, is how the grass is going to be maintained after installation by either the homeowner or a professional crew. Some grasses look fine when mowed with a rotary mower, others look best when cut by a reel mower. Other grasses are more or less susceptible to chemical damage, scalping, fungus or disease. These are issues that may require some professional intervention.

Marsh cites two zoysias as an example. Palisades zoysia is a medium-bladed grass, while Cavalier zoysia is finer-bladed. “Some grasses are very forgiving and very durable,” Marsh says. “Palisades would be very forgiving where Cavalier is not. If Cavalier gets damaged from scalping or chemicals, it’s such a slow grower that it’ll take time to repair itself.”

Travis Meacham is president of the Washington Turfgrass Seed Commission and manager at Friehe Farms, a producer of Kentucky bluegrass seed in Moses Lake.

“One thing a landscaper should be looking for is a seed or sod that has gone through a certification process,” Meacham says. Certification, he explains, ensures “that the grass you’re buying is the variety the seller says it is and that it’s weed-free.”

State certification agencies inspect seed and sod fields for genetic purity, weeds, pests and diseases. Without certification, Meacham says, there’s no guarantee that the grass you’ve carefully researched and selected is the grass you’re actually receiving. Certification provides that extra layer of insurance.

While many factors play into the success or failure of a grass project, cost is often the first consideration. Client budgets and financial restrictions are a fact of doing business, but buying the cheapest grass or sod available is not necessarily the best decision in the long run. Grass that is uncertified, full of weeds or wrong for the location leads to unhappy customers — or worse, the need to patch or replace entire jobs. When all of these factors are considered, choosing a lower-cost grass may end up costing you far more in the long run.

Making the decision

With all of the different species, climates, soils and cultivars to consider, what’s the best way to come to a decision about which grass to plant? By gathering as much information as you can regarding the project’s needs and researching all the species and varieties whose characteristics best meet those needs. And by checking with the client’s HOA, city or township for any requirements that may affect your choice.

Cox says local sod farms are excellent resources for learning which varieties consistently thrive in your climate zone. Before you buy, though, Marsh suggests you consider a sod or seed provider’s customer service, quality and ease of delivery.

You can get expert advice from local agricultural extension offices. Most land-grant or state universities have them, and they’re typically staffed by certified master gardeners or turfgrass researchers.

The internet makes it easy to compare the performance and characteristics of different cultivars. Research organizations such as the National Turfgrass Evaluation Program publish their research online.

And, of course, consult with your clients to learn how they intend to use their lawns. If kids and pets will be romping on it or students or shoppers beating paths through it, wear tolerance may be of overriding importance. If the main purpose of a lawn is to add curb appeal to a home or to give a corporate quad a well-manicured look, grasses with finer-textured leaf blades may be called for. If a location has poor water quality or a lot of trees that will throw shade, those elements must be considered too.

If you do your homework, talk with experts and most importantly, your client, you’ll come to the decision that puts both of you comfortably in the green zone.

The author is a turfgrass marketer and founder of What’s Your Avocado? Marketing and Public Relations, Mount Vernon, Washington, which specializes in turf and green industry marketing. She can be reached at stacie@whatsyouravocado.com.