Flatsedges, also called Nutsedges, are members of the genus Cyperus in the sedge family (Cyperaceae). The sedge family also contains sedges, bulrushes, and spike rushes. The sedge family is closely related to the grass family, and sedges are commonly mistaken for grasses.

Many flatsedges have tuberous roots that help them survive our dry summers but can also contribute to aggressive behavior in gardens. Two non-native flatsedge species, Purple Nutsedge (Cyperus rotundus) and Variable Flatsedge (Cyperus difformis), are common lawn weeds in the Woodland area. However, native flatsedge species are important components of our local ecosystem.

Native Species

Perennials

Tall Flatsedge (Cyperus eragrostis) is a fast-growing, 3-foot-tall perennial flatsedge that is native to Woodland and to most of Yolo County, especially the Sacramento Valley parts of the county. It usually grows in wet areas and prefers full sun. It is not picky about soil textures. It is ranked 7 out of 10 on the Ogren Plant Allergy Scale, indicating that it tends to cause fairly severe hay fever.

Yellow Nutsedge (Cyperus esculentus), also called Chufa Sedge, is a fast-growing, 8-inch-tall perennial flatsedge that is native to Woodland, Davis, West Sacramento, the eastern slopes of the Dunnigan Hills, and all parts of Yolo County to the east of those locations. It usually grows in wet areas. It is not picky about soil textures. It is ranked 7 out of 10 on the Ogren Plant Allergy Scale, indicating that it tends to cause fairly severe hay fever.

False Nutsedge (Cyperus strigosus) is a two- to three-foot-tall perennial flatsedge that is native to Woodland, Knights Landing, the eastern slopes of the Dunnigan Hills, and the area in between those three points. It usually grows in wet areas and prefers loamy or clay soil in full sun or partial shade. It is ranked 7 out of 10 on the Ogren Plant Allergy Scale, indicating that it tends to cause fairly severe hay fever.

Annuals

Red-Rooted Flatsedge (Cyperus erythrorhizos) is a three-foot-tall annual flatsedge that is native to Woodland and to most of Yolo County, especially the Sacramento Valley parts of the county. It grows only in wet areas but prefers sandy or loamy soil. It prefers full sun. It is ranked 7 out of 10 on the Ogren Plant Allergy Scale, indicating that it tends to cause fairly severe hay fever.

Fragrant Flatsedge (Cyperus odoratus) is a one- to two-foot-tall annual flatsedge that is native to Woodland and to most of Yolo County, especially the Sacramento Valley parts of the county. It usually grows in wet areas but prefers sandy or loamy soil. It is ranked 7 out of 10 on the Ogren Plant Allergy Scale, indicating that it tends to cause fairly severe hay fever.