Battling a lesser-known invasive on Sanibel
The Sanibel-Captiva Conservation Foundation reported that Sanibel is home to an extensive variety of invasive exotic flora and fauna. Most invasive species, such as Brazilian pepper and the cane toad, are well-known to the general public. However, a lesser known but extremely prolific invasive exotic — cogon grass — has invaded portions of the island’s natural ecosystems.
For seven years, SCCF’s Wildlife & Habitat Management has been treating 25 cogon grass infestation sites ranging in size from a few square meters to several thousand square feet, SCCF Land Steward Victor Young said. A biannual treatment, utilizing a combination of herbicides recommended by the Florida Department of Agriculture and University of Florida Institute of Food and Agricultural Sciences, simultaneously targets the foliage and the root system to maximize control.
“These treatments have shown significant success on Sanibel by either eradicating cogon grass from specific sites or reducing the area affected by nearly 90 percent,” Young said.
A native to Southeast Asia, cogon grass was initially introduced to Alabama in 1912 as packing material in fruit crates. It was subsequently introduced to other Gulf coast states for cattle feed, although ranchers would soon discover that it was not a palatable source of forage. Cogon grass would also be utilized for erosion control in various places throughout Florida in the early 1900s.
It is extremely adaptive to a variety of climates and habitats — excluding wetlands — and thrives in disturbed soils, often spreading through wind-driven seed or agricultural equipment. Additionally, cogon grass is a pyrogenic plant, meaning it is well-adapted to fire. Due to these adaptations, it eventually outcompetes nearly all native vegetation. Over 1 million acres of pasture, timberland and environmentally-sensitive habitats in the southeastern United States have been negatively impacted.
“Although cogon grass can be difficult to manage or eradicate, it is thankfully easily identified,” Young said.
The grass blades can reach nearly 6 feet tall and typically range from dark green to light green in color. The most prominent indicators are the white off-center midrib, serrated margins, and a white, puffy spike-like panicle inflorescence. Mature stands of cogon grass often develop dense mats of cream-colored rhizomes.