Plant holds potential in lawn applications

Ornamental peanut sod, supplied by Sunset Specialty Groundcovers, is installed in large roll form. The plant can also be installed as small individual plants, which will spread out and fill in any open areas.
PHOTOS COURTESY OF SUNSET SPECIALTY GROWERS.

They say that big things come in small packages, and the peanut plant seems to prove that point. Known for producing tiny nuts, the plant may just hold huge potential for the green industry.

University of Florida researchers have been studying ways that the rhizoma perennial peanut plant (a “distant cousin” to the food-producing crop) might be used as a ground cover in ornamental landscape settings, and even in turf-like lawn applications. Professor Ann Blount has been researching the perennial peanut as a forage crop for many years. “In her breeding work, she recognized the ornamental potential of the dwarf types that had been ignored in the forage world,” explains Gary Knox, a professor of environmental horticulture at the North Florida Research and Education Center in Quincy, Fla. Blount contacted Knox, and the two began examining possible landscape uses of perennial peanut about a year and a half ago.

Rhizoma perennial peanut features very dense, low-growing characteristics that make it attractive as a ground cover.

The University of Florida already has released two types of rhizoma perennial peanuts—Arblick and Ecoturf—as a way of building interest in the plant. These two types can be used in either forage or ornamental settings, and are free for anyone to grow and use. Some ornamental producers have added these to their offerings. For example, Sunset Specialty Groundcovers in Jacksonville, Fla. (www.ornamentalpeanut.com), offers these plants in both individual plant and even sod forms. In fact, that company has been growing various types of ornamental peanuts for about 14 years, explains Patti Veale, nursery manager. “In the beginning, they were used mainly in landscape settings,” she says

Now, as water restrictions have curtailed the use and performance of turfgrass in some areas, Sunset Specialty Groundcovers is seeing more of a demand for ornamental peanuts as a grass-like ground cover in large, open areas. “If you water it even twice a month during a drought, it will look great,” Veale explains. She says that without any water the plant may brown out, but will green up again once it receives water. Not surprisingly, this ability to conserve water and still thrive is attracting a lot of interest.

Perennial peanuts can handle some foot traffic, and researchers are envisioning a day when the plant will be blended with turfgrass. Currently, the plant is used mainly in areas that don’t receive heavy wear and tear.

“Highway departments are installing miles of it in medians and along roadsides. Golf courses are even using it on [out of play] hills for erosion control,” says Veale. In those cases, the customers generally opt to purchase large (30-inch-by-80-foot) sod rolls for easy installation and an instant green cover. In smaller applications, including some home lawns, customers buy individual plants and “plug” them in, she adds. The rhizomatous plant will then spread and fill in the entire area.

The result is a peanut lawn that requires very little water. “As a rhizomatous plant, it has a very extensive system of deep roots and rhizomes, so it’s very efficient at extracting water from soil,” explains Knox. “There are more than one kind of perennial peanut, but in general, these are nitrogen-fixing legumes that form very dense, spreading ground cover that can be anywhere from several inches high in landscape types to 12 or 18 inches in the forage types.”

Currently, University of Florida researchers are evaluating a whole host of other selections that are being compared to Ecoturf and Arblick, explains Knox. “A graduate student is ‘characterizing’ these different selections, and he has field plantings at two locations in Florida, and a container study going on. So, we’re going to get some good information,” he says.

Two of the characteristics getting particular attention are the shade and cold tolerance of different rhizome perennial peanut selections. “There’s a tropical form called Arachis pintoi that’s used in Central America, the Caribbean and south Florida, but it’s not cold hardy much north of Orlando,” explains Knox. “So, the species that we’re focusing our research on is Arachis glabrata. That is considerably tougher and is cold hardy through zone 8a. And, we’re hopeful of finding even more cold-tolerant forms.” All species of peanut are from South America, and Blount is currently looking for higher elevation forms with more cold tolerance, he adds.

With the selections already released, in winter months, the plant dies back to the ground and re-emerges in the spring. “It’s really quite fast-growing once it re-emerges,” says Knox. In late spring, the plant develops yellow flowers, which provide a stunning look and contrast with the green of the plant itself.

Some of the selections that University of Florida researchers are looking at are more low-growing and broad-leafed than the Ecoturf variety, which has already been released. Ecoturf can be mowed, if desired. “But, you would only need to mow it two or three times per year,” explains Veale. She adds that this has proven to be a popular characteristic with those looking to cut down on the costs and emissions associated with mowing.

“Generally, each selection has a mature height that it will reach relatively quickly, and it just doesn’t grow much taller,” explains Knox. “We frankly don’t know a lot about the type of mowing frequency that different selections will require. A lot of it will be dependent on weed control during establishment—just as it is when establishing any lawn grass. And, being a newer plant, there aren’t as many [weed control] products available for it yet, so I imagine [in lawn applications] that some mowing will be a part of weed control, at least initially. If used simply as a ground cover bed, mowing might not be necessary at all.”

In addition to using less water and requiring fewer mowings, there are other potential savings that can be realized, as well, with perennial peanut ground covers. In comparison to turfgrass, the plant requires much less fertility. “Its needs are very minimal once it’s established,” says Knox. Potassium, phosphorus or sulfur might be needed in forage settings, where the plant is regularly harvested, or during establishment in landscape settings, but nitrogen is rarely needed in any of these scenarios. “Containers aren’t the real world, but in one of our early studies we saw it do very well without any nitrogen at all,” he explains.

One common question has to do with wear tolerance of the peanut plant. “Obviously, as a forage plant it’s quite resilient,” says Knox. “Whether it’s in a pasture setting where cattle eat it, or whether it’s baled for hay, it’s very resilient at coming back and able to handle cattle traffic. It can take light traffic well, as long as you don’t use on a sports field or on a walkway, I think it would be fine. We’re not sure yet if it will handle football players. I’m a little doubtful about that, but you never know.”

Veale says her experience shows that ornamental peanut does very well in handling regular foot traffic and at least normal amounts of wear and tear.

Because it requires less water, fertility and mowing than most turfgrass species, the perennial peanut is being installed in a variety of landscape settings.

Knox feels that installing the peanut plant in a pairing with turfgrass might help improve the performance characteristics of each. “I think there is a lot of potential to blend rhizome perennial peanut with lawn grasses, in the hopes that the nitrogen-fixing perennial peanut might be able to provide some of the nitrogen requirements of the lawn grass, and provide some ability for fast growth and filling in,” he explains. “And, the grass could supply some of the wear resistance and durability.” Knox views the plant as “not a competitor for turfgrass, but as a companion for turfgrass.”

Knox is not sure yet exactly how that pairing between peanut and turfgrass will work, but the University of Florida is currently seeking research grants to help study exactly that type of scenario. “It will depend very much on the type of lawn grass you use, as well as the selection of rhizomatous peanut you use. And then, you have to determine the ratio of each to use, and what mowing regime to use. There are a lot of variables to work out before we have a product,” he says.

Another group interested in finding new selections for this unique plant is the Perennial Peanut Producers Association (www.perennialpeanuthay.org), whose members grow products for a variety of both forage and ornamental applications. With water restrictions increasing and water costs rising, the perennial peanut is sure to continue attracting attention outside of industry and university circles, as well. “It’s wide open right now. We have some solutions already, and we’re working on even better solutions,” says Knox. “It’s really exciting. Nothing is perfect, but this looks good and is definitely worth pursuing.”

Patrick White is a freelance writer and editor who has covered every aspect of the green industry in the past 13 years. He is based in Middlesex, Vt., and is always on the lookout for unusual stories.