A new invasive species wants into the Alleghanies
It grows on every continent except Antarctica and has earned a reputation as one of the worst weeds on earth. Now, cogongrass is one of the most threatening invasive species in the South.
Native to Southeast Asia, cogongrass was accidentally introduced in 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 stablilizer in Florida. And then it began to spread. Because cogongrass is fast moving and a destructive plant that can thrive almost anywhere, the entire South is at risk for invasion. Each cogongrass plant produces as many as 3,000 wind dispersed seeds. It can also spread by underground stems known as rhizomes that form dense mats reaching deep into the soil. If you have ever tried to remove bamboo, you know what this is like. Cogongrass apparently tolerates all light and soil conditions except dense shade and permanently wet soil. Fire won’t kill it. The rhizome root system allows it to quickly regenerate. It burns readily, even when green, and will greatly increase fire spread.
The range of cogongrass has been limited to temperate areas with relatively mild winters…so far, but that may be changing. Red Baron or Japanese blood grass an ornamental variety of cogongrass used in landscape plantings, is cold hardy. As of yet, this cultivar does not produce seed, but it does have viable pollen. This means that there is real potential for the cold hardiness bred into the ornamental varieties to be imparted to invasive cogongrass populations through pollen. This concern has caused several Southern states to prohibit the sale and distribution of ornamental cogongrass. Virginia has not yet regulated these ornamentals. When shopping for ornamental grasses for your landscape, keep cogongrass in mind. It wasn’t long ago that our part of the Alleghanies was thought to be too cold for Kudzu to survive. We now have Kudzu established in several areas in both Alleghany and Bath counties.