Alligator Weed

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Alligator weed (Alternanthera philoxeroides) is one of the most difficult aquatic weeds to control. It grows in a wide range of soil and water conditions. It may be found free-floating, loosely attached, rooted, emerging from the water, or in a dry field. It generally grows as a mat of interwoven plants. The leaves are opposite, glossy, lance-shaped, 2 to 5 inches long, and have a distinct midrib. Flowers are white and resemble clover blooms. Stems are usually hollow. To view photos of this plant, click here.

Alligator weed was introduced from South America and has become a serious pest. Found mainly in the southern half of Mississippi, it is most common in the coastal areas. Read and follow label instructions before using any chemical in water. The treatments listed on the treatments page will usually give good results, although re-treatment may be necessary.

Professionals have given particular attention to make certain all herbicide treatments have been registered with the Environmental Protection Agency for use in the manner described. Registrations for specific practices are often changed or deleted; therefore, treatments suggested in this information sheet may not remain current indefinitely. Read and observe the manufacturer's label to prevent misuse of a herbicide. It is not intended or proposed that usage of any given practice suggested at this site be in violation with existing registration or manufacturer's label.

If you fail to carefully read and follow suggested treatments, you could cause extensive damage to the environment, crops, livestock or humans.