Once a familiar, unwanted neighbor for Mobile County farmers, cogongrass has spread to pastures, forestland, fields and roadways in over a dozen states.
Anthony Faggard of Grand Bay in Mobile County said the aggressive, exotic, perennial grass has boxed in most of his fields.
“It’s been here on the farm all my life,” said Faggard 53, Alabama Farmers Federation State Beef Committee chairman. “It’s expensive to try to keep it contained. The problem we have with trying to spray it in fields is the effective herbicides also will kill the Bahia grass we use for hay or grazing.”
Cogongrass, introduced to Mobile from Japan in the early 1900s as packing material, covers 75 percent of the state and is regarded as one of the worst invasive species in the world.
“I would rank cogongrass up there with wild hogs,” said Nancy Lowenstein, an Auburn University School of Forestry and Wildlife Sciences research fellow. “It grows aggressively. Even when you burn it, it comes rip-roaring back.”
Loewenstein copublished a study in 2014 that may offer farmers a better outlook. She treated cogongrass infestations for three years at Tillmans Corner and Bayou La Batre using glyphosate, imazapyr and a combination of both sprays in May, August and October. Almost all of the nine treatments eradicated cogongrass, but imazapyr proved most effective, she said.
“One thing we definitely found is that all cogongrasses are not equal,” she said. “Each location varied in its response to the spray applications. We’re still working on exactly why we had two different reactions at different sites.”
While cogongrass can be spread by seeds blown by the wind or transported through farm equipment, it also spreads underground by rhizomes that form thick root masses in a circular pattern, which make it even tougher to control.
Washington County landowner and Federation State Forestry Committee Member Emory Mosley said cogongrass is a consistent problem on his land.
“The longer it stays in one place, the longer it takes to get rid of it and control it,” he said. “If it gets established, it’s hard to get it with chemicals. Sometimes it’s better to burn and saturate the young growth, but you have to be careful because it’s very volatile in a fire.”
Cogongrass is tough and unpalatable to cattle and other livestock, said Federation Beef and Hay & Forage Divisions Director Nate Jaeger.
“It has little nutritional value, but cattle will graze it if it’s young and tender,” Jaeger said.
In thick stands, the highly flammable grass can create a fire hazard, and the heat can be so intense it may stress mature pine stands and lead to disease and insect infestations. Dense stands of cogongrass also destroy wildlife habitat by choking out native grasses. If left unchecked, it can quickly become the dominate understory, choking out desirable vegetation.
Whether it’s with cattle, pine trees or a research farm, Faggard, Mosley and Loewenstein agree the fight against cogongrass should be a united front.
“There’s no silver bullet—you just have to keep at it,” Loewenstein said. “It’s really hard if only one person is working to eradicate cogongrass because it doesn’t stop at boundary lines.”