Cogongrass (Imperata cylindrica) is an agressive, perennial grass from Southeast Asia. Introduced into the United States on at least two separate occasions, this weed is currently invading Florida, Alabama, Mississippi, and Louisiana and has recently been discovered in East Texas. Cogongrass is considered one of the 10 worst weeds worldwide and is a pest in at least 73 countries. Although the transport of this plant into and throughout the United States is prohibited by federal law, cogongrass continues to spread throughout the southeast gulf coast threatening forests, rangelands, natural areas, roadsides, and residential areas.
WHY IS COGONGRASS A PROBLEM?
Cogongrass is an aggressive invader capable of displacing native vegetation,desirable pasture grasses, and tree seedlings in a wide range of soil types and conditions.
HOW DO I KNOW IT'S COGONGRASS?
Cogongrass is a yellowish-green, fibrous grass of variable size.
HOW IS COGONGRASS CONTROLLED?
An integrated approach that targets cogongrass rhizomes is required to provide long-lasting control. Repeated deep cultivation during the dry season can effectively dessiccate rhizomes, although tillage combined with a systemic herbicide (i.e., glyphosate) is more effective. Where cultivation is not possible or desirable, a combination of burning or mowing with repeated herbicide applications can control cogongrass. Burning or mowing alone stimulates cogongrass and so must be followed by herbicide. Burning or mowing is needed to remove dead biomass so the herbicide can be applied to actively growing leaves. Systemic herbicides are most effective when applied in the fall when cogongrass is storing carbohydrates in the rhizomes. Immediate revegetation of the area with more desirable species and retreatment of newly sprouting cogongrass with herbicide are necessary for effective control.
The text for this page was prepared by Sharon King.