Imperata cylindrica

cogongrass, alang-alang, blady grass, cogon grass, kunai, paillotte, santintail


Leaf Arrangement


Leaf Type


Growth Form


Flower Color


Flower Month

May - June

Height (meters)

0.3 - 1.2

Milky Sap








Growing Season

Warm season

Prairie Coefficient of Conservatism


Field Characters

Identified in the field by coarse, wide leaves with an off centered midvein (see photo).

Cultural Information

Reproduces from seed and rhizomes. Seeds average approximately 2,200,000/lb.

Natural History

A weed that has recently been recognized as a major problem in the southeastern United States. It was first introduced accidentally, as packing material, near Mobile, Alabama during the winter of 1911-1912. It was reintroduced at the Mississippi Agricultural Experimental Station as a potential pasture grass. It was recognized as a potential weed in farmland in the late 1940s but no action was taken. By 1968 it had infested 10,000 acres in Mobile County. Listed as number seven on the list of worlds worst weeds, it may be found in 73 countries. It recovers rapidly from disturbance due to a vigorous root and rhizome system. It is also resistant to damage from fire actually benefiting in many cases. It is found on a wide variety of soil types and ecological settings but is intolerant of shade and cold. It flowers in May but also flowers after frosts and other disturbances. It produces up to 3000 seed per inflorescence which are wind disbursed. It is reported to be allelopathic and extracts inhibit corn, sorghum and other crop plants. Native plants are also excluded from Cogon stands greatly reducing biotic diversity where Cogon invades. It is reported from Alabama, Florida, Louisiana, Mississippi, Oregon, and South Carolina (USDA 1998). A small population has now been reported from east Texas.