Nutsedge (Cyperus spp.)
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Nutsedges are perennial weeds in the sedge family and superficially resemble grasses. They are among the most problematic weeds of agriculture in temperate to tropical zones worldwide. They are difficult to control, often form dense colonies, and can greatly reduce crop yields. In California, nutsedges are particularly problematic in summer-irrigated annual and perennial crops. Yellow nutsedge, Cyperus esculentus, grows throughout California to an altitude of roughly 3300 feet (1000 m). Purple nutsedge, Cyperus rotundus, is not as widespread in California, but does grow in the Central Valley, South Coast, and low desert, to about 820 feet (250 m).
Seedlings are rarely found. Seedling leaves look similar to that of mature plants, but are smaller and finer. The stem base is slightly triangular and the midvein area is usually pale. The first two to three leaves emerge together, folded lengthwise.
Nutsedges grow mainly from tubers formed on underground, horizontal creeping stems called rhizomes, mostly in the upper foot of soil. Sprouts from tubers are similar in appearance to the mature plant.
Sedge stems are erect and hairless. Although sedge leaves superficially resemble grass leaves, they lack collars, ligules, and auricles. Sedge leaves are thicker and stiffer than most grasses, are V-shaped in cross-section, and arranged in sets of three from the base rather than sets of two as found in grass leaves. Sedge stems are triangular in cross-section; grass stems are hollow and round. Yellow nutsedge stems grow to 3 feet (0.9 m) tall and its leaves are light green, and have pointed tips. Purple nutsedge stems grow to 1-1/3 feet (0.4 m) tall and have dark green leaves with rounded leaf tips. Tubers of yellow nutsedge are produced singly while purple nutsedge tubers are produced in chains, with several on a single rhizome.
Purple nutsedge spikelets are dark reddish to purplish brown. Yellow nustsedge spikelets are straw-colored to gold-brown with many flowers.
Yellow nutsedge has tiny, single-seeded fruit (achenes) that are football shaped, triangular in cross-section, and brown. Purple nutsedge does not typically produce seeds in the United States.
Both nutsedge species reproduce by underground tubers that are attached to underground stems. Yellow nutsedge also produce seed in California, but they have low viability and are not considered a more source of reproduction and spread.
Related or similar plants
- Yellow Nutsedge, Cyperus esculentus
- Purple Nutsedge, Cyperus rotundus
- Green kyllinga, Kyllinga brevifolia
- Smallflower umbrella sedge, Cyperus difformis