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Yellow Nutsedge (Cyperus eragrosts)

Class B Noxious Weed in Benton County


Identify:

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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.

 Yellow Nutsedge Before Flowering

Yellow Nutsedge Before Flowering

 Yellow Nutsedge After Flowering

Yellow Nutsedge After Flowering

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.

Mechanical:

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.

Chemical:

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.


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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.