LDWF issues advisory on spread of cogongrass

Invasive exotic species is now in most of Southeast Louisiana; early treatment is key to long-term control

The Louisiana Department of Wildlife and Fisheries is advising private landowners that cogongrass, which grows in dense mats and rapidly displaces native vegetation, is spreading into much of Southeast Louisiana, as well as some western and central parishes.

According to a press release, the invasive exotic weed grows in dense mats and rapidly displaces native vegetation, eventually converting acres of once productive habitat into ecological deserts void of almost any desirable plants.

Now is the time to identify and treat it. Identification is easy since it is typically found in dense, often circular patches, void of any other grasses or forbs.  The leaves are long and slender, up to 6 feet long and 1 inch wide, but more commonly about 2 to 3 feet long and ¾ of an inch wide.  The leaves are a light yellowish-green, and the midrib is offset to one side.  It flowers in late March to mid-June and produces cylindrical fluffy white flower heads 2 to 8 inches long.  The seeds are light and carried by the wind, similar to those of a dandelion.

For a long time it was thought the grass was uncontrollable, but research revealed that treating stands of cogongrass for three consecutive years with a mixture of glyphosate and imazapyr herbicides has been effective, the release states.

Treatments should occur in May, August or October, and LDWF recommends addressing the plant when it first appears. Left unmanaged, the grass will take over pine stands, pastures, roadsides and anywhere else it becomes established.

If you suspect you have this weed growing on your property and need assistance with identification and treatment recommendations, contact your local LDWF private lands biologist.  LDWF Wildlife Division field offices and phone numbers are: Monroe (318-343-4044), Minden (318-371-3052), Pineville (318-487-5885), Lake Charles (337-491-2575), Hammond (985-543-4777), Opelousas (337-948-0255) and New Iberia (337-373-0032).

Click here for more information, or contact Jimmy Ernst with LDWF by calling 985-543-4784.