Ricefield flatsedge is a tufted, tropical annual or perennial sedge in the Cyperaceae family. Native to tropical and subtropical locations, it is commonly found growing in the southeastern US in areas of marshes, swamps, ditches, and low wasteland. It can be found growing in rice paddies and other wet places around the world in tropical locations and is a major weed in rice, cotton, soybean and other crops. In native conditions, it can flower year round, in US locations, it will flower in the summer and fall. It can be found as far north as Maine. Its flowers are each encased in two glumes, a membrane that surrounds the flowers of a sedge. Multiplies rapidly by the 3,000 to 5,000 seeds produced on each plant. It has the ability to establish a second generation of plants in a single season. It has numerous, fibrous, yellow-red short roots. Management of this weedy plant can be done by hand, performing weeding prior to the flowering and the production of seed. It can also be controlled chemically.
Curated pairwise relationships between this plant and others in the library — who feeds
whom, who competes, who confuses the pests. Green reads as a good pairing, red as one to avoid.
No curated interactions recorded for this species yet.
Also noted by NC State
Related species the NC State Plant Toolbox flags for this plant — look-alikes to tell
apart, and plants that play a similar role in a planting. Ones we carry in the library are linked.
The flat, lance-linear green leaves are scabrid (rough) on the margins and mid-rib (having small, sharp projections) and V-shaped. The leaf sheath is reddish-brown and wraps around the stem. The leaf sheaths are green, shorter than the stem and surround the stem at the base.
Flower color
Gold/Yellow; Green
Flower form
Spike; Umbel
Flower size
< 1 inch
Flower detail
Flowers are produced in open, compound umbels on spikes that are subtended by 4-7 leaf-like bracts. The spikes are golden-brown in color, usually sessile, elongated and golden to yellowish-green.
Bloom time
Fall; Spring; Summer; Winter
Fruit color
Brown/Copper
Fruit type
Achene; Nut
Fruit size
< 1 inch long, < 1 inch wide
Fruit detail
The fruit is an shiny, obovoid, brown achene having three sides.