Six Rivers CISMA EDRR Invasive Species of the Month – Guinea Grass

EDRR Invasive Species

Guinea Grass (Megathyrus maximum)

Guinea Grass
Photo: UF IFAS


Define Invasive Species: must have ALL of the following –

  • Is non-native to the area, in our case northwest Florida
  • Introduced by humans, whether intentional or accidental
  • Causing either an environmental or economic problem, possibly both

Define EDRR Species: Early Detection Rapid Response.  These are species that are either –

  • Not currently in the area, in our case the Six Rivers CISMA, but a potential threat
  • In the area but in small numbers and could be eradicated

Native Range:

Guinea grass is native to Africa.



The plant was introduced as livestock fodder.


EDDMapS currently list 2,614 records of guinea grass.  Most records come from Florida and Texas, but it has also been reported in Hawaii and Puerto Rico.  In Florida it has been reported across the state.  There are 17 records in the Florida panhandle, 15 of those within the Six Rivers CISMA, 12 of those within the CISMA were reported from the Yellow River Preserve area in Santa Rosa County and the remaining three were from Eglin AFB.



This is a large panicum grass reaching heights of up to seven feet and grows in dense mats.  The strap-like blades and smooth and up to three feet long and two inches wide.  The seed inflorescence is large as well, reach two feet in length.


Issues and Impacts:

Guinea grass is an aggressive growing plant that will quickly occupy disturbed open spaces and form thick monocultures decreasing native plant abundance and overall biodiversity.



The recommended management is foliar spraying with a 1% solution of glyphosate.  Care should be taken not to overspray because this herbicide is non-selective and will kill other desirable plants.


Please report any sighting to


For more information on this EDRR species, contact your local extension office.



Urochola maximum. Guinea Grass.  University of Florida Center for Aquatic and Invasive Species.  | Center for Aquatic and Invasive Plants | University of Florida, IFAS (


Sellers, B., Smith, H., Ferrell J. 2018. Identification and Control of Johnsongrass, Vaseygrass, and Guinea Grass in Pastures. University of Florida Electronic Data Information System.  SS-AGR-363. pdf\AG\AG372\AG372-16272415.pdf (


Early Detection and Distribution Mapping System (EDDMapS)


Six Rivers CISMA


Posted: May 12, 2022

Category: Invasive Species, Natural Resources
Tags: EDRR Species, Guinea Grass, Invasive Species, Six Rivers

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