World's #7 Most Invasive Weed - Cogongrass

Cogongrass is rapidly spreading across Mississippi and is showing no signs of letting up. This very aggressive weed is capable of taking over low maintenance sites by out competing more desirable vegetation. It has been found in Adams, Amite, Claiborne, Franklin, and Jefferson Counties.

Cogongrass is commonly found in circular patches and can spread rapidly. The density of cogongrass patches (80 - 90 stems/ft2) and its aggressive nature allows it to out-compete other beneficial vegetation. Cogongrass is established in new sites by wind blown seed or movement of contaminates soils. Once a patch is established it spreads through rhizomes, a thick system of underground stems capable of producing new roots and shoots. This rhizome mass is extremely dense making this a difficult plant to destroy.

This grass is easily identified when growing in patches because of their circular nature. It also blooms and produces a white feathery seed head early in the spring (March to May). The offset midrib on the leaf blade is another characteristic that can be used as identification. Another key is the rhizome mat that forms in the upper four to six inches of the soil.

Once this grass is positively identified every effort should be made to control it and prevent its spread. Glyphosate (Round-up or generic brand) and Arsenal are the two most effective herbicides for controlling cogongrass. To totally eliminate this grass the root mass has to be killed, so it may take multiple treatments over a couple years to control this pest. The most effective way to fight cogongrass is to prevent it from becoming established.

Cost-share programs are available for landowner fighting cogongrass. The Mississippi Forestry Commission, NRCS, and Mississippi Department of Agriculture are assisting landowners through funding control efforts when money is available. If you suspect cogongrass is on your property, you should contact the MSU Extension Service or the NRCS office to have it positively identified. Once it is confirmed to be cogongrass begin control efforts as quickly as possible.