Cogon Grass: Imperata cylindrica
Cogon grass leaf blades can grow to 4 feet tall and can be
easily identified by its leaf blades having a midvein noticeably
Look for first
- Off-center midrib on leaf blades, more apparent towards the tip
of the blade
||Leaves: Leaf sheaths relatively short,
glabrous or pubescent; ligule a membrane, 0.5-1 mm long. Leaf
blades erect, narrow and pubescent at base, flat and glabrous
above, to 1.2 m (4 ft) tall and to 2 cm (< 1 in) wide, with
whitish midvein noticeably off-center; blade margins scabrous,
blade tips sharp pointed.
||Flowers: Inflorescence a narrow, dense
terminal panicle, white silky and plumelike, to 21 cm (8 in) long
and 3.5 cm (1.5 in) wide. Spikelets crowded, paired on unequal
stalks, with each spikelet surrounded by long white hairs
Cogon grass is considered to be one of the top 10
worst weeds in the world and has extensively invaded north and
central Florida disturbed areas and pinelands. This perennial
grass from Southeast Asia was introduced into the U.S. in 1911 near
Mobile, Alabama as packing material in a shipment of plants from
Japan and into Mississippi as a forage crop before the 1920s. Later
it was introduced into Florida for forage and soil stabilization.
Cogon grass was then found to be unsuitable for forage and its
ability to rapidly spread and displace desirable vegetation
outweighed any soil erosion control considerations. Cogon
grass has extensively invaded disturbed areas such as roadsides and
fallow pastures throughout north and central Florida but also
relatively undisturbed sandhill and pine flatwoods.
Commonly found in humid tropics but has spread to warm temperate
zones worldwide. Found throughout the southeastern U.S. and widely
established in Florida.
Cogon grass forms dense stands that
displace native plant communities. Because of its rough edges
and silica bodies found throughout the leaves, it is mostly
unpalatable to native wildlife species. Because of its dense, thick
growth pattern, cogon grass degrades native gopher tortoise and
indigo snake habitats in Florida.
Cogon grass stands can create a severe fire hazard especially
when mixed in with other volatile fuels such as young pine trees.
Fires occurring in cogon grass infested woods have significantly
increased native tree mortality.
Why Cogon Grass must be managed
Cogon grass forms dense stands resulting in the almost total
displacement of native plants that are important to wildlife. Cogon
grass stands also represent a significant fire hazard on public
conservation lands and agricultural forests.
grass (Imperata cylindrica)
Image Credit: LeRoy G. Holm