Cogon Grass

Cogongrass

The Perfect Weed

Cogongrass (Imperata cylindrica), an invasive plant of Asian origin, poses a significant threat to Mississippi and the southeastern United States. It is believed to have ‘escaped’ from an orange crate at the Port of Mobile, AL, in the early 1900s and has proliferated in the last few decades. This weed, once used as a packing material and still sold as an ornamental plant, spread rapidly by colonizing disturbed soils and encouraging more frequent wildfires, which, for a fire-adapted and highly flammable species like cogongrass, is the perfect storm. Land managers and Consulting Foresters, with the assistance of Mississippi State University’s Extension Service, have worked hard to find a solution to this growing problem.

The available interdictions for cogongrass are limited. Usual methods of invasive species control are not just ineffective, but contributory to its spread. A prescribed burn at any time encourages the proliferation of cogongrass, endangering other species. Highly flammable cogongrass burns at temperatures high enough to kill even fire tolerant species, namely young loblolly and longleaf pines. The use of fire plows raises the risk of dragging rhizomes to uninfected areas.

Tillage, while adequate if maintained over long periods of time, thereby exhausting the energy reserves of cogongrass rhizome layers, can and will promote growth if abandoned. In addition to the need to continue tillage until the entire rhizome layer is energy-depleted, care must be taken to clean any equipment used to avoid spreading rhizomes to previously unexposed areas. Vehicles entering forests from infested areas must take the same care to avoid transporting rhysomes or seeds and contributing to its spread. Several decades ago, cogongrass was visited as a possible source of nutrition for grazing livestock, but it was quickly abandoned because it was found to be all but useless due to its high silica content and low forage quality. Cattle will graze on young shoots, but as the plant matures, it sits uneaten. Some cattle producers have taken to mowing cogongrass to encourage the new growth for their herds to feed on, but this is an ineffective and unsustainable method of control

Care must be taken by landowners, Foresters, and researchers to cease the spread of this threat to the environment. Cogongrass is a resilient enemy, growing in wetlands and drylands, organic and clay soils, full sun and shade. Once established, it often forms monocultures, essentially wiping out other species. It is highly adaptive to harsher environments, establishing itself in soils unfit for most plants, and its natural consumers are rare.

In our next blog, we will discuss methods of cogongrass control that have proven more effective at slowing its spread. Until then, please call Southeast Forestland LLC with any questions or concerns regarding this subject. If you have a cogongrass infestation, we will be glad to devise a strategy to help you mitigate the problem.