It grows on every continent except Antarctica and has earned a reputation as one of the worst weeds on earth — and according to U.S. Forest Service emeritus scientist Jim Miller, cogongrass (Imperata cylindrica) is without doubt one of the most threatening invasive species in the South.
In addition to cogongrass, it goes by other common names: alang-alang, blady grass, kunai, paillotte, and santintail.
Native to Southeast Asia, cogongrass was accidentally introduced into the United States as packing material in an orange crate that arrived in Grand Bay, Alabama, in 1912. A few years later, it was intentionally planted as a potential forage crop in Mississippi and as a soil stabilizer in Florida. And then it began to spread.
SRS Forest Inventory and Analysis data indicate that cogongrass currently grows on over 66,000 forested acres — and counting — throughout the southern U.S. “This does not take into account the thousands of unsurveyed acres occupied by cogongrass in nonforested settings,” says Miller. “Because cogongrass is a fast moving and destructive plant that can thrive almost anywhere, the entire Southeast is at risk for invasion.”
Each cogongrass plant produces as many as 3,000 wind-dispersed seeds that can germinate on disturbed soil. Cogongrass also spreads by underground stems known as rhizomes that form dense mats reaching deep into the soil. The rhizomes have pointed tips that are sharp enough to pierce the roots of nearby plants. Rhizome shoots and branches expand into colonies that can completely exclude all other plants.
From the USFS Southern Research Station: https://www.srs.fs.usda.gov/compass/2016/08/09/cogongrass-continues-to-invade-the-south/