This month, NAISMA’s “Know Your Invasives” campaign highlights a tenacious and ecologically disruptive plant: Cogongrass (Imperata cylindrica). Originally brought to the United States for erosion control and livestock forage, it has since become one of the most problematic invasive species across the southeastern U.S. Now it’s spreading rapidly, affecting ecosystems and communities alike.

What is Cogongrass?

Cogongrass is a perennial grass native to Southeast Asia that arrived in the United States in the early 1900s. This grass quickly adapted to its new environment, thriving in disturbed and natural areas alike, including forests, pastures, roadsides, and along waterways. Its capacity to grow in dense, expansive mats gives it a competitive edge, allowing it to outcompete and displace native plants and diminish biodiversity.

Why is it a Problem?

Cogongrass is highly aggressive, and its spread has numerous negative impacts on ecosystems, agriculture, and even human safety. Here’s a closer look at the key issues associated with this invasive species:

• Ecological Disruption: Cogongrass forms dense stands that prevent native plant species from establishing and thriving, resulting in reduced biodiversity. The native plants displaced by Cogongrass serve as habitat and food sources for local wildlife, so their loss can disrupt entire ecosystems.
• Increased Fire Risk: One of the most dangerous characteristics of Cogongrass is its extreme flammability. Its dry, dense foliage can ignite quickly, leading to hotter, more intense wildfires than those fueled by native vegetation. These intense fires can damage trees and other fire-adapted plants that typically withstand natural, lower-intensity fires.
• Agricultural Threats: Cogongrass can invade pastures, croplands, and orchards, reducing forage for livestock and competing with valuable crops. Because it’s nearly impossible to control with grazing or mowing, farmers and land managers find it especially challenging to manage.

How Does Cogongrass Spread?

It spreads both by seed and vegetatively through its rhizomes (underground stems). A single Cogongrass plant can produce thousands of seeds, which are then carried by wind, water, animals, and even human activity. Its dense rhizome network allows it to survive fires, droughts, and even some herbicides, making eradication efforts particularly difficult.

Humans play a significant role in the plant’s spread, often inadvertently transporting seeds or rhizomes through contaminated soil, equipment, and vehicles. This resilience and adaptability have allowed it to establish populations across various states, particularly in the Southeast.

Current Control and Management Strategies

Controlling Cogongrass requires an integrated approach that may include:

• Chemical Treatments: Herbicides are currently the most effective option for controlling Cogongrass. However, repeated applications over several years are often needed due to its extensive rhizome system.
• Prescribed Burns: When used carefully, controlled burns can reduce the above-ground biomass of Cogongrass, making it easier to apply herbicides to the regrowth. However, burning alone is ineffective for eradication because of the plant’s ability to resprout from rhizomes.
• Public Awareness and Prevention: Educating landowners, recreational users, and the general public about the dangers of Cogongrass and how to prevent its spread is essential. Simple actions like cleaning equipment, vehicles, and shoes before leaving an infested area can help slow its spread.
• BioControl Efforts: Read more here.

What Can You Do?

If you live or work in areas where Cogongrass is a threat, you can help prevent its spread by:

• Learning to Identify Cogongrass: Familiarize yourself with Cogongrass’s appearance—its distinctive fluffy white seed heads, dense stands, and sharp, pointed leaves with an off-center midrib.
• Reporting Sightings: Report any suspected Cogongrass sightings to local invasive species or agriculture departments. Early detection and rapid response are key to managing new infestations.
• Cleaning Equipment and Gear: Make it a habit to clean boots, tires, and outdoor equipment after being in areas where it or other invasive species may be present.

Join the Fight Against Invasive Species

Cogongrass is a potent example of how an invasive species can profoundly alter landscapes and disrupt ecosystems. Together, we can work to curb its spread through increased awareness, vigilance, and sustainable management practices. Every action, no matter how small, helps protect our ecosystems from the far-reaching impacts of invasive species like Cogongrass.

For more information about Cogongrass and other invasive species, visit our “Know Your Invasives” campaign page or consult the U.S. Department of Agriculture and local environmental agencies. By staying informed and proactive, we can make a difference in safeguarding our natural landscapes for generations to come.

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