Photographer: Richard Carter Affiliation: Valdosta State University Source: www.bugwood.org Copyright: CC BY 3.0 US
Grows in robust, loose clumps to up to 40 inches high; leaves are V-shaped and glossy. Leaf bases are distinctly purplish-black. Culms (stems) are strongly 3-sided. The inflorescence is terminal and consists of 5 - 11 groups of densely clustered spikelets, which are greenish-white. Culms are connected by thick rhizomes.
Rapidly spreading from disturbed to natural areas. It can form monocultures, displacing native vegetation in habitats it invades. Construction, agricultural activities, and roadside mowing are spreading the seeds and dispersing this plant to new areas. Once established, it out competes native grasses and sedges, threatening local plant biodiversity. It alters habitat for the endangered Attwater's prairie chicken. It is a potential pest to rice agriculture.
An aggressive seed producer; large plants can produce 1 million viable seeds/year. Seeds are readily transported by water. This plant will flower and fruit from June through November. Also reproduces vegetatively via fragmentation and budding of rhizomes.
Most likely introduced via rice agriculture and was first reported in Texas from Cameron County about 20 miles north of Brownsville in 1941. It continues to spread especially along roadsides via mowing, flooding, and soil and equipment movement. Unfortunately, it wasn’t recognized as a threat to the United States until 1990.
Native Origin: South America
U.S. Habitat: Thrives in disturbed, inundated soils. Will form monospecific stands in ditches, coastal prairies, low flatwoods, and fallow rice fields. Tolerant to various soil textures (sands to clays).
U.S. Present: AL, FL, GA, LA, MO, MS, SC and TX
For a distribution map provided by EDDMapS click here
Resembles: Cyperus entrerianus can resemble other Cyperus species.
Native alternatives include Big bluestem (Andropogon gerardii), Sideoats grama (Bouteloua curtipendula), and Starrush whitetop (Rhynchospora colorata).
Glyphosate is expected to achieve 98% control when applied at a rate of 2 quarts/acre. Use a 2% solution on individuals. Mowing at 2-4 week intervals suppresses seed production. Machinery should be kept clean to prevent seed spread.
USE PESTICIDES WISELY: Always read the entire pesticide label carefully, follow all mixing and application instructions and wear all recommended personal protective gear and clothing.
Researchers in Texas have been performing studies to see how the plant responds to herbicides (imazapic) in combination with prescribed fire. Preliminary evidence shows that this combination might prove to be successful in the Texas Coastal Prairies.
Contributions from Texas Invasives for this species page are greatly appreciated.
Bryson, C. T., & Carter, R. (2008). The significance of Cyperaceae as weeds. Sedges, uses, diversity, and systematic of the Cyperaceae, Missouri: Monogr Syst Bot Mo Bot Gard, 108, 15-101.
Carter, R. (1990). Cyperus entrerianus (Cyperaceae), an overlooked species in temperate North America. SIDA, Contributions to Botany, 69-77.
King, J. R., Bennett, A. J., Conway, W. C., Rosen, D. J., & Oswald, B. P. (2015). Response of Deeproot Sedge (Cyperus entrerianus) to Herbicide and Prescribed Fire in Texas Coastal Prairie. Invasive Plant Science and Management, 8(1), 15-31.
Rosen, D.J., R. Carter and C.T. Bryson. (2006). The spread of Cyperus entrerianus (Cyperaceae) in the southeastern United States and its invasive potential in bottomland hardwood forests. Southeastern Naturalist 5:333-344.
The Quiet Invasion: A Guide to Invasive Plants of the Galveston Bay Area.
Internet Sources:
http://www.valdosta.edu/~rcarter/Rosen.Carter.Bryson.2006.pdf
http://www.texasinvasives.org/plant_database/detail.php?symbol=CYEN2
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