Many times referred to as the World’s Worst Weed. Yellow nutsedge is frequently mistaken for a grass because of its narrow, grass-like leaves. It is easily distinguished from grasses by its triangular (three-ranked) solid stem. Its leaves are V-shaped long and slender. A perennial from 1 to 2 feet tall with a shiny light yellow-green color. Yellow nutsedge has an extensive underground system of rhizomes and tubers (nutlets). Nutlets are brown to rust colored, about ¼ to ½ in in diameter and are usually in the upper 6 inches of soil. Straw colored seedheads are formed near the top of the plant and resemble bottle brushes. Seeds are produced in the millions per acre, but are generally of low quality, making nutlets the primary source of propagation. Each plant will produce several hundred to many thousands of nutlets per season with multiple eyes each, which can persist in the soil for several years.

An intractable problem in production agriculture and extremely expensive to manage. In turf lawn and ornamental plantings, it is very difficult to control. At the first sign of invasion it is advisable to remove as much of the plant as possible, before the formation of nutlets. If nutlets are present removal is crucial to success, which requires the sifting of the top 6 inches of soil. There are some herbicide choices available, however it would be advisable to seek professional help. In waste areas or places where they can be used there are several effective residual herbicide choices. Dense shading crops or ornamental plants help to reduce pressure. No biocontrols are yet available.
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Modified from Selected Noxious Weeds of Eastern Oregon, Gary Page, Malheur County Weed Inspector.