One tough nutsedge
Editor’s note: This article is from the archives of the MSU Crop Advisory Team Alerts. Check the label of any pesticide referenced to ensure your use is included.
As we reach the Fourth of July weekend, I’ve been seeing more and more yellow nutsedge (Cyperus esculentus) infesting lawns. As referenced from www.msuturfweeds.net, we often see more yellow nutsedge infestations in years with above normal rainfall and the year following. Last year certainly had plenty of rainfall and depending on your location, this year has been pretty consistent with moisture.
Yellow nutsedge is often called nutgrass or swampgrass. It’s not a broadleaf, it’s not a grass, it’s a sedge and is easily identified by the triangular shape of the stem. If you roll the stem between your fingers you should be able to feel the triangular shape of the stem. Other distinguishing characteristics of yellow nutsedge include leaves that are light green to yellowish in color and waxy or slick to the touch. Yellow nutsedge grows rapidly, and the leaves are often seen several inches above the turfgrass canopy. Nutsedge produces tubers or nutlets underground that really make controlling this weed difficult. These tubers can remain dormant in the soil for several years and sprout new plants when moisture becomes available. Nutsedge is also a prolific seed producer with each plant potentially producing 2,400 seeds. The old saying of one year’s seeding is worth seven years weeding would probably be adapted to 20 years weeding for nutsedge.
There are options for controlling or eliminating nutsedge. The first step is to keep up on your mowing schedule to prevent seed production. Hand weeding may be effective, but remember that those little tubers under the surface will simply sprout a new plant, so if you like pulling weeds this may be your dream weed, it’ll come back time and time again. For serious infestations, a herbicide application may be necessary. Control options for homeowners are rather limited, look for products with the active ingredient sulfentrazone. Yellow nutsedge control options for professional applicators include Certainty (a.i. sulfosulfuron) and Sedgehammer (a.i. halosulfuron). Repeat applications will likely be required to achieve control. As with any herbicide applications at this time of year, be cautious of applications to turfgrass that is under drought or heat stress. General recommendations are to avoid herbicide applications when temperatures are above 80°F due to the risk of burning the turf.