Cogon Grass - Imperata cylindrica
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Imperata cylindrica is a perennial rhizomatous grass native to east and southeast Asia, India, Micronesia and Australia. It grows from 0.6-3 m (2-10 feet) tall. The leaves are about 2 cm wide near the base of the plant and narrow to a sharp point at the top; the margins are finely toothed and are embedded with sharp silica crystals. The main vein is a lighter colour than the rest of the leaf and tends to be nearer to one side of the leaf. The upper surface is hairy near the base of the plant while the underside is usually hairless. Roots are up to 1.2 meters deep, but 0.4 m is typical in sandy soil.
The plant has become established as a weed in the Americas, Northern Asia, Europe and Africa in addition to many islands and is listed as an invasive weed in many areas. In the U.S. it survives best in the southeast, but has been reported to exist as far north as West Virginia and Oregon. Worldwide it has been observed from 45°N to 45°S. It grows on wet lands, dry lands, areas of high salinity, organic soils, clay soils and sandy soils of pH from 4.0 to 7.5. It prefers full sun but will tolerate some shade.
It is an aggressive plant which is spread both through small seeds, which are easily carried by the wind, and rhizomes which can be transported by tilling equipment and in soil transport. The rhizomes create dense mats on the ground surface reducing the chances of the seeds of other plants reaching the soil and germinating successfully.
In the Southeastern United States, state governments have various eradication efforts in place. Control is typically by the use of herbicides. Burnoff is seldom successful since the grass burns quite hot causing heat damage to trees which would ordinarily be undamaged by a controlled burn and recovers from a burn quickly.
Silica crystals in its leaves deter all but the most desperate animals from eating its low food value leaves. The crystals cut the mouth and probably wear down teeth. It forms a very dense mat which prevents much competition from other plants. It may release an allelopathic phenoic chemical that may kill other plants or prevent seeds from germinating. The strong sharp tipped rhizomes penetrate the roots of other plants, perhaps to weaken them or leave them open to infection.
It is because of these reasons that the overall fodder value is very much reduced, and because of its ability to survive, it is considered to be an invasive pest in warmer climates.
Cite this Wikipedia article
"Imperata cylindrica." Wikipedia. Wikipedia, 2007. Answers.com 13 Jul. 2007. http://www.answers.com/topic/imperata-cylindrica
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For more information on this plant or management please contact US Army Corp of Engineers