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Cogongrass: 'weed from hell' spreadingCogongrass: 'weed from hell' spreading

  “Cogongrass is so aggressive, if left unchecked it can replace an entire ecosystem,” says Jim Hancock, invasive plant control program coordinator for the Mississippi Forestry Commission at Brookhaven. It has been called “the weed from hell” and “the mother of all invasive species.”

Hembree Brandon

December 3, 2010

10 Min Read


I woke up this morning,

I looked out at my fields.

What I saw out there,

It made me want to squeal.

Them little white flowers,

They was growin’ everywhere.

It’s enough to make a man

Pull out all his hair.

I got the cogongrass blues.

What am I gonna do?

I got the cogongrass blues…


It may not make the Hit Parade, but “The Cogongrass Blues,” a ditty by The Blues Rangers band, mirrors the woes of landowners in Mississippi and other southern states who’ve seen their pastures, forest lands, and wildlife/recreational areas gobbled up by a weed that many liken to an invasion of aliens in a sci-fi movie.

And like the movie monsters, the grass just keeps spreading and spreading.

It has been called “the weed from hell” and “the mother of all invasive species.”

“It is so aggressive, if left unchecked it can replace an entire ecosystem,” says Jim Hancock, invasive plant control program coordinator for the Mississippi Forestry Commission at Brookhaven.

It is so solidly entrenched in many areas of Florida — with more than a million acres infested — that, he says, “It will still be there when Jesus returns.”

Like kudzu, another “foreigner” used for early era erosion control, the grass is spreading rapidly across the South — now as far west as eastern Texas and as far east as South Carolina.

In addition to Florida, heaviest infestations are now found across broad areas of southern Georgia, Alabama, and several counties of south Mississippi, and a multi-million dollar effort is now under way to try and curb its advance northward.

In 1979, only 19 counties in southern Mississippi had infestations; today it is in 50 counties across the state and continuing to spread.

Mississippi has just finished the first year of spraying in a $1.1 million suppression program, while Alabama has a $6 million-plus eradication program in progress.

“We’re running a lean, mean operation — everything we’re doing is geared to the spray program,” says Hancock, who briefed landowners on the weed and the control effort at a meeting at Starkville, Miss.

Cogongrass (Imperata cylindrica), thought to have originated in southeast Asia, is designated by many authorities as the seventh worst weed in the world. It is found in 73 countries on all continents.

Came into U.S. in 1912

It was introduced into the U.S. at Grand Bay, Ala., in 1912 as packing material for a shipment of satsuma orange rootstock from Japan. It was later used in Mississippi and Florida in forage test trials and for erosion control.

Various cultivars (Japanese bloodgrass and Red Baron grass among them) have been used by landscapers and new varieties continue to be introduced, much to the dismay of invasive plant managers and researchers.

No northern boundary for overwintering has been established, but researchers say most of the eastern U.S. and Pacific Northwest may also be at risk.

In a video presentation, “Cogongrass — The Perfect Weed,”

produced for the Mississippi Coastal Plains Resource Conservation & Development Council, Inc., which serves six coastal counties — George, Hancock, Harrison, Jackson, Pearl River, and Stone — Randy Browning, U.S. Fish and Wildlife Service/Mississippi Fish and Wildlife Foundation, says cogongrass “has no known value and no known enemies.

“Researchers found out pretty quickly it had no value as a forage crop because of its high silicon content.”

The grass spreads by seeds and by underground rhizomes. Its fluffy white seedheads can produce up to 3,000 seeds which, like dandelion seeds, can be blown up to 15 miles by winds, and are transported by animals when the seeds are caught in their fur.

Spreading also occurs from rhizomes and seeds on earthmoving and road maintenance equipment that has been used in infested areas. Land managers working on food plots and loggers often spread the grass in moving from one area to another, as do fire plows when wildfires occur.

“It takes four weeks from time a mature seed germinates until it starts producing rhizomes,” Browning notes. “With good soil and moisture conditions, it can spread up to 43 square feet from the time it germinates. Across an entire landscape, it doesn’t take long for an exponential spread.

The grass is also allelopathic — it produces chemicals that suppress growth of other plants.

“All this is a bomb waiting to happen,” Browning says.

Thinning of commercial pine plantations, which opens up the canopy and allows more sunlight, often opens the door to cogongrass invasion, which can quickly spread throughout the forest understory, hampering productivity of the trees and choking out desirable wildlife habitat.

Expense to fight grass "enormous"

Judd Brooke, a Hancock County, Miss., landowner, says the expense of fighting the grass has been “enormous — but we had to do it, because it was starting to smother out areas of the forest — there was no natural vegetation at all; it even choked out yaupons and wax myrtles. It was totally changing the characteristics of the forest. In areas where we were planting trees, no seedling would grow, the plant and root mass is so thick.”

J.B. Brown, a Stone County timber producer, says, “Until we thinned pines about five years ago, didn’t notice much cogongrass, but after thinning it was sprouting everywhere.

“It also has a negative impact on wildlife. Birds won’t consume the seeds. The grass is so thick, there’s no way turkey poults or quail chicks can navigate through it; they can’t nest in it or forage in it”

Randy Merritt, Mississippi Forestry Commission ranger, says cogongrass represents a major fire threat.

“Due to its high vegetative density and biomass, burning grass produces a very volatile fire that can reach temperatures of up to 850 degrees with flames five feet high, and spread very quickly. This high heat usually kills trees and surrounding vegetation, as well as endangering homes and farm buildings. If there’s any wind, we have trouble with it jumping firebreaks. Even with no wind, it’ll spread much faster than any other kind of fire, and it’s extremely hard to extinguish.”

John Byrd, Jr., Mississippi Extension professor of weed science, says one of most important identification features of cogongrass is that it blooms in the spring.

“It grows during summer, but unlike other warm season grasses, except zoysia, it blooms immediately after turns green for summer growth, and then forms white, fluffy seedheads.”

Another identification feature is its rhizome system. “Johnsongrass has rhizomes, but cogongrass rhizomes arefar more extensive and numerous,” he says. “Each of the many nodes on a rhizome is capable of producing roots and a new plant above ground. Over 60 percent of the plant’s biomass is in roots and rhizomes, and that’s what you have to kill to completely eradicate a population.”

Herbicides for control program

Two products are available for use in a control program, Browning notes — glyphosate (Roundup ProDry) and imazapyr (Arsenal Powerline and Chopper). Recommended rates for foliar application, he says, vary from 2 percent to 3 percent percent glyphosate product to 1 to 1.5 percent Arsenal products.

“You can safely use Arsenal around pine trees and it will hammer cogongrass,” he says. “I prefer a mixture of 1.5 percent solution of Roundup with 1/2 percent to 1 percent of Arsenal and a good surfactant, which gives a good synergistic response.

“Be aware, though, you can’t use this mixture around hardwoods; in those areas, you’ll have to use only a glyphosate product. It will take more applications, but over a period of time you can take out the grass. The more you can do to cogongrass, the more control you’ll get.”

Jim Hancock says the Mississippi spray program isn’t using the herbicide mixture. “We feel we get a more permanent kill with the Arsenal products. We use a 2 percent solution and spray enough to thoroughly wet the plants.”

In agricultural or pasture environments, disking the ground will put additional stress on the cogongrass, Browning says. “Deep disking will knock it back; continued deep disking will really hamper it. If you can mow or burn the grass, come back and disk, then let it sprout back up and apply herbicide, it will be more effective than just one spray application or one technique alone.

“But, you have to be vigilant in going back to see how well the herbicide applications have worked and which areas you may have missed. In one field that was sprayed three times with Roundup, there were still spots coming back. So, you may have to spot treat over two or three years. Be sure to spray 6-8 feet beyond visible cogongrass to get any tillers.”

Charles Bryson, USDA/ARS botanist, says cogongrass similar in invasiveness to kudzu. “It has not yet reached level of importance of kudzu, but has potential to spread and become as bad or worse than kudzu.”

In 1948, Browning says, Weed Scientist R. L. Pendleton warned, “Steps should be taken at once to completely eradicate this noxious weed from the Western Hemisphere.”

“Now, in the 21st century, we’re behind the curve,” he says. “It’s time to get busy working on stopping this pest. Fortunately, a lot of groundwork through Mississippi’s Bureau of Plant Industry and the Mississippi Department of Agriculture and Commerce.

“But landowners, land managers, utility rights-of-way managers, and others need to start being very aggressive with cogongrass, and work on it week-to-week, year-to-year. A one-time application won’t do it — we’re going to have to be very vigilant.”

Applications for spraying program

Hancock says the state is continuing to take applications for participation in the cogongrass spraying program.

“We have over 600 applications at this point, and thus far we’ve sprayed for 300 to 400 people.

“If someone requests assistance, we’ll come out and walk over the property with a GPS unit, then overlay locations of cogongrass on an aerial map. Our contractor can then use the GPS coordinates to go right to the infestations. We’ll be mapping all winter and expect to start spraying again about May 1.”

There is no cost to landowners, he notes. They need only to sign a contract and release. If they have cows on the land, they have to either take them off prior to treatment, or if they leave them on the land they must agree not to take them to market for at least 30 days following treatment.

“This can be an effective program if everyone works together,” Hancock says. “But it’s not something to be complacent about — if you think just a few plants can’t constitute a problem, you need to go to South Mississippi or Florida and see what it has done there. It can radically change an entire ecosystem.”

Julie White, Extension director for Oktibbeha County, says “There are spots of it pretty much everywhere in this county. The main thing in controlling it is persistence — making a control effort part of a good land stewardship program. If we do this, we’ve got a good chance of keeping it from getting out of control like it has done in south Mississippi and other areas.”

USDA also has a program that has been renewed for another year, Hancock notes, that will provide herbicide to landowners for cogongrass control. NRCS also offers a 75 percent/25 percent cost share through its EQIP program.

Cogongrass plants are more easily identified in the fall, says John Byrd.

“They stand out better in the landscape than in the spring when everything is green. Also helping to confirm ID are the sharp-pointed rhizome tips that protrude from the soil surface — but be cautious, they’re like a toothpick; they will pierce your skin and it hurts like the devil.”

For more information

• The Mississippi Landowners Assistance Program to help suppress cogongrass spread is cost-free to eligible landowners. It is made possible through an American Recovery and Investment Act of 2009 stimulus grant. Administered, with oversight by the USDA Forest Service and implemented by the Mississippi Forestry Commission.

It is available in Attala, Choctaw, Clarke, Clay, Kemper, Lauderdale, Leake, Lowndes, Neshoba, Newton, Noxubee, Oktibbeha, Scott, Webster, and Winston Counties.

• For more information, contact the Mississippi Forestry Commission Invasive Plant Control Program: 1-877-708-7651 or check the website www.mfc.ms.gov for details. The program will also provide assistance to landowners in identifying cogongrass.

• The informative video, “Cogongrass — The Perfect Weed,” may be viewed online at http://www.mfc.state.ms.us/Videos/Cogongrass.wmv

• The Blues Rangers Band is Dave Allen, wildlife biologist, and Tate Thriffiley, district ecologist, for the DeSoto National Forest in Mississippi. They perform all over the U.S. and have recorded two nationally-distributed CDs of blues songs highlighting current natural and cultural resource management issues.

Their Blues Rangers Interpretive Program is a public outreach and environmental education tool designed to entertain and inform audiences of all ages and to encourage appropriate public use and stewardship of national forests and grasslands, as well as other public and private lands. Further information is at http://www.fs.fed.us/r8/mississippi/desoto/blues_rangers.shtml and www.myspace.com/thebluesrangers

About the Author(s)

Hembree Brandon

Editorial director, Farm Press

Hembree Brandon, editorial director, grew up in Mississippi and worked in public relations and edited weekly newspapers before joining Farm Press in 1973. He has served in various editorial positions with the Farm Press publications, in addition to writing about political, legislative, environmental, and regulatory issues.

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