News Releases

FWC addresses invasive plant growth in St. Johns River

News Release

Tuesday, October 13, 2015

Media contact: Greg Workman, 352-620-7335; Diane Hirth, 850-410-5291

The Florida Fish and Wildlife Conservation Commission (FWC), in partnership with the St. Johns River Water Management District and Brevard County, this month will be managing invasive West Indian marsh grass in portions of the St. Johns River.

Herbicides will be used from Oct. 15 to 30 on portions of the river between Highways 520 and 50, if weather permits.

Applications of glyphosate and imazapyr aquatic herbicides will be made by using airboats. Glyphosate and imazapyr are approved for use in rivers and lakes by the U.S. Environmental Protection Agency and Florida Department of Agriculture and Consumer Services. There are no restrictions on the use of water in the treatment area for recreational purposes, including swimming and fishing. The treatments are planned to protect flood control areas, restore native plant communities and support recreational boating and other aquatic activities on the river.

West Indian marsh grass (Hymenachne amplexicaulis) is an extremely invasive exotic plant species. It is known to choke out native habitats and form monocultures where it becomes established. These dense monocultures diminish habitat quality for migratory bird species, including waterfowl and wading birds. Presently, this invasive species is growing within the St. Johns River and associated marshes.

The FWC’s plan is to continually manage this species to eliminate its presence and prevent it from establishing on the St. Johns River. Managing and treating this nonnative plant is necessary for the health of Florida’s waters.  For questions about these management activities, contact C.J. Greene, FWC invasive plant management biologist, at 321-246-0505.

For “Frequently asked questions” about removal of invasive plants, go to: and select “Invasive Plants.”

West -Indian -marsh -grass

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