Forestry & Wildlife

Stop Cogongrass Hitchhikers

2 min read
Figure 2. Cogongrass infestation showing the typical yellowish green color of the leaves.

Cogongrass is an aggressive weed that is rapidly spreading across Alabama and the Southeast. Learn important steps you can take to slow the spread of this environmental invader.

Cogongrass (Imperata cylindrica) is a noxious weed that reduces forest productivity, destroys wildlife habitat, and affects rights-of-way. It can spread quickly by hitchhiking on skidders, road graders, mowers, food plot equipment, and other forest and road maintenance equipment (figure 1).

By following these three steps, you can help to significantly slow the spread of cogongrass.

Step 1: Learn to Identify Cogongrass

  • Leaves are 1⁄2 to 1 inch wide and 1 to 5 feet tall. Leaf margins are finely serrated (rough). The leaves are often yellowish green (figure 2) with a whitish midrib that may be off-center, especially near the base of the leaves. Leaves turn a distinctive reddish tan color in winter (figure 3).
  • Flowers are 2 to 8 inches in length and silvery white when mature. The seeds are light and fluffy, like dandelion seeds. Flowers bloom in spring or early summer, or after a disturbance (figure 4).
  • Plant bases have no apparent stems, so leaves appear to arise directly from or close to the ground. Plants are more spread out than clumped.
  • Rhizome/roots grow in a dense mat of light-colored rhizomes (underground stems), which are covered in flaky scales, are strongly segmented, and have sharp points.
  • Whole plants grow in dense, often circular patches.

Step 2: Avoid Cogongrass

  • Cogongrass is spread by windblown seeds and underground rhizomes, which have buds that can start new plants (figure 5). Seeds or pieces of rhizomes that move to new areas in soil, hay, or sod, or on equipment can easily sprout and start new infestations.
  • Do not mow, bushhog, or even enter cogongrass infestations when seed heads are present.
  • Do not work in cogongrass when soil is muddy and rhizomes easily can break off and stick on equipment.
  • Do not grade or push roads or fire lines through cogongrass. If this is unavoidable, try to work in contaminated sites last.

Step 3: Clean Vehicles, Equipment, and Clothing After Operating in Infested Areas

If you must work in areas infested with cogongrass, clean vehicles, equipment, and clothing before moving into an uncontaminated area. Cogongrass is classified as a federal and state noxious weed, and it is illegal to transport plants, seeds, or plant parts. Cleaning vehicles and equipment in the field may be challenging, but it is necessary to stop the spread of cogongrass, and it will keep you from breaking the law.

Areas to Check and Clean

  • Radiator, grill, undercarriage, and tops of vehicles
  • Blades and under the deck of bushhogs, mowers, etc.
  • Tires, rims, and tracks
  • Places where seeds and rhizomes can stick to grease and mud (seals, bearings, etc.)
  • Clothing (especially wrinkles and cuffs)

A broom and shovel may be the most practical tools to dislodge seed and rhizome material. If available, a pressure washer is especially effective for cleaning vehicles and equipment. However, in the field, follow best management practices:

  • Do not wash off parts of the machine that have oil buildup.
  • Do not use chemical detergents.
  • Do not wash vehicles or equipment where water runoff can reach a stream.
  • Clean in an open site that can be monitored and where new cogongrass plants can be eradicated.
  • Schedule thorough cleanings at a garage or other facility as often as possible.

 

For more information about cogongrass and its control, visit www.cogongrass.org.

 

Nancy J. Loewenstein, Extension Specialist, Forestry and Wildlife Sciences, Auburn University

Reviewed March 2023, Stop Cogongrass Hitchhiking, ANR-1321

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