Imperata cylindrica
Family: Poaceae

Natural History
Thick growth of cogongrass
Photo credit: SFRC, University of Florida

Cogongrass is considered to be one of the 10 worst weeds in the world. It is a perennial, nonnative grass that spreads quickly due to high seed production and extensive rhizomes.


Identifying Characteristics

Habitat: Cogongrass is found on dry land and partially flooded areas. It often grows in disturbed areas and creates a dense mat of roots and leaves that prevents other plants from growing.
Size/Form: Cogongrass generally grows to a height of 3', although it can sometimes get much taller. It has many long, narrow leaves that emerge at ground level without any visible stem. Out of sight below ground, the plant has an extensive network of rhizomes.
Leaves: The leaves are about an inch wide, have a prominent white midrib, and end in a sharp point. Leaf margins are finely toothed and are embedded with silica crystals. The upper surface of the leaf blade is hairy near the base; the undersurface is usually hairless.
Flowers: The flowers are arranged in a silvery, cylindrical, branching structure about 3" to 11" long and 1½" wide. Numerous seeds are produced (as many as 3,000 per plant) which can be wind-dispersed over long distances.



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