Maryland Grows

You may have suddenly noticed yellow nutsedge (Cyperus esculentus) crowding into your mulched garden beds or lawn in late summer/early fall. Also known as “chufa sedge, tiger nut, or earth almond,” this charismatic and fascinating plant was one of humanity’s earliest cultivated plants. It is still cultivated and considered a culinary treat in North and West Africa, western Europe, and China for its nutritious nut-like tubers attached to underground stems known as “rhizomes.” 

Yellow nutsedge can be identified by its yellowish coloration, stiff triangular stem, and three long leaf bracts at the base of a puffy brown flower. It tends to thrive in sunny areas with moist, disturbed soils.  While similar in appearance to straw-colored flatsedge (Cyperus strigosus), it can be distinguished by its small, nut-like tubers. One yellow nutsedge plant can produce thousands of tubers, which allows it to produce more vegetation in the spring. Yellow nutsedge flowers in late summer and early fall and is a wind-pollinated plant that cannot self-pollinate.

Yellow nutsedge colonized North America before Europeans did, so it is considered native here by some sources. In Maryland, it is most abundant in the Piedmont and Coastal Plain ecoregions.  It is often treated as an aggressive agricultural and lawn weed across the U.S. because it can quickly take over disturbed areas and may outcompete lawn or garden plants. It tends to thrive in mulched beds and lawns that are overwatered or mowed too short.

To remove yellow nutsedge manually, you’ll have more success starting early in the season, when the plants have fewer than five small leaves. If you’re pulling in late summer or early fall, once flowers have developed, you might leave tubers and rhizomes behind in the soil that will only multiply. So, if you’re trying to manage its spread, try to remove as much of the underground plant material as possible, then stay on top of pulling it early when it emerges again next summer. You might also consider re-planting the area densely with a variety of native plants suited for sunny, moist conditions, then stay on top of weeding in spring.

If you choose to make peace with yellow nutsedge as part of your landscape, however, you can take comfort in knowing that its large underground biomass contributes organic matter and aeration to clay soils, improving water infiltration and soil structure for enhanced plant growth. It also makes a greater contribution to biodiversity than turfgrass – it’s a food source for Wild Turkeys and a wide variety of mammals that root up the tubers, and it is noted by the Maryland Biodiversity Project to be a larval host plant for the Dun Skipper (Euphyes vestris).

By Stacy Small-Lorenz, Ph.D., Residential Landscape Ecology Specialist, University of Maryland Extension. Read more posts by Stacy.