This aggressive weed forms dense stands over large areas and can eliminate native plants.
• By Amanda Huber •
“Cogongrass is one of the most serious invasive species in the southeast,” says Justin Ballew, Clemson University Cooperative Extension. “This time of year it’s in full bloom and easy to identify, so now is when state regulators are out visiting and monitoring populations.”
Described by Clemson University’s Department of Plant Industries (DPI) as a plant species that could be far worse than other rampant exotics like kudzu, invasive cogongrass is considered to be one of the top 10 worst weeds in the world. It was first found in South Carolina in 1987 at a site in Hampton County that is still active.
Call If Found
The department is charged with the eradication of this plant and has treated all reported infestations, but new sites are found each year. Left unchecked, this aggressive weed forms dense stands over large areas and can virtually eliminate native plants. Cogongrass is mostly unpalatable to livestock and wildlife and can create a significant fire hazard.
Ballew urges anyone who believes they have cogongrass on their property, to contact the Clemson DPI immediately so that control may be initiated.
“Take a look at the information on how to identify cogongrass,” he says. “The map shows the counties in South Carolina where cogongrass has been recorded. If you live near one of those counties especially, be on the lookout.”
Do Not Dig
Cogongrass (Imperata cylindrica), an Asian native grass, is a federally regulated noxious invasive weed that can easily displace native plants that are used by birds, animals and insects for forage and shelter. The weed also poses a threat as a fire hazard. Cogongrass burns very hot and will burn beneficial plants commonly managed with fire.
Cogongrass is spread by both windblown seeds – a single plant can produce 3,000 seeds – and underground branching rhizomes. Each rhizome, or fragment of rhizome, can start a new plant.
Seeds or pieces of rhizomes moved to new areas in soil, hay or sod, or on equipment can easily sprout and start new infestations.
Producers are asked to not dig up cogongrass patches in an effort to remove the weed, but to instead call their Extension agent who will put them in contact with the proper authorities on invasive weed species in their respective state. Several states have a cogongrass task force who work to verify and properly document weed sightings and will assess the situation to determine the best way to eradicate the weed.
What To Look For
The leaves of cogongrass are 0.5 to 1 inch wide, and it grows 1 to 6 feet tall. The edge of leaves is rough like sandpaper, and it is often yellowish- green with white midrib that is generally off-center, especially near the base of the leaves.
Flowers grow 2 to 8 inches in length and are silvery white. Seeds are also silvery white and are light and fluffy, blowing off like dandelion seeds.
Cogongrass blooms in spring or early summer or after a disturbance. Plant leaves appear to come out of the ground with no apparent stem. Plants are more spread out than clumped.
Underground, light-colored rhizomes and roots form a dense mat, and rhizomes are covered in flaky scales and
are strongly segmented with sharp points. The whole plant grows in dense, often circular, patches.
Take Action On This Weed
Remember to clean vehicles, equipment and clothing if it is suspected that you were operating in an infested area.
If working in areas infested with cogongrass is unavoidable, clean vehicles, equipment and clothing before moving to an uncontaminated site. Because cogongrass is classified as a federal and state noxious weed, it is illegal to transport plants, seeds or plant parts.
For more information about cogongrass and its control, visit www.cogongrass.org or contact your county Extension office. South Carolina producers can contact the Department of Plant Industry at 864-646-2140 if cogongrass is suspected in your area.