Yellow Nutsedge (Cyperus eragrosts)
Class B Noxious Weed in Benton County
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Yellow Nutsedge is a perennial that can be mistaken for a grass. This sedge grows to be 1-3 feet tall. The leaves are narrow, yellowish green, waxy, smooth, and shiny. These leaves have a prominent midvein and taper to a pointed tip. Stems of yellow Nutsedge are triangular in a cross-section. Flowers grow in clusters and are golden brown in color with bracts at the base. Seeds are also yellowish brown and are three-angled and 1/16 of an inch long. Yellow Nutsedge reproduces by rhizomes and tubers as well as by seed. Each tuber, it’s primary mode of reproduction can have 5-7 buds that can germinate into new plants.
Methods of Control:
Yellow Nutsedge can be difficult to control because the plant can quickly regenerate from tubers that are left behind. Tubers stay viable in the soil for 3 to 4 years.
Manual control is effective for small infestations if you remove all the root systems. Tilling can potentially spread tubers. Continually hand-pulling or tilling at four-week intervals can help to deplete the carbohydrate reserves in the roots over time.
Specific herbicides are required to achieve control, and the herbicide must out last the tuber’s ability to re-sprout. There are products that are selective and will not kill grass that work on Yellow Nutsedge. Refer to the PNW Handbook for more information. Always read and follow the label.
Although Yellow Nutsedge can be a problem in your lawn...
Yellow Nutsedge can also be a severe problem in vegetable crop production. Yellow Nutsedge is highly adaptable in irrigated areas and reduces crop yields.