YYellow nutsedge, Cyperus esculentus, is a member of the sedge family although it closely resembles a grass. In fact one of its frequently used common names is yellow nutgrass. It is a common weed in Nebraska lawns and landscapes, and can often be found in areas with moist soil. Yellow nutsedge is a warm season perennial plant, meaning that the below ground portion of each plant survives the winter and generates new top growth each spring.
When closely examined, yellow nutsedge is found to have a very unique form and can easily be distinguished from turfgrasses and other grassy weeds. The leaf blades are light green, “V” shaped with a prominent ridge down the center of the leaf blade and mostly originate from the base of the plant. The leaf blades always seem to grow faster than the surrounding grass, sticking up above the turf only a few days after mowing. When examined in cross-section the lower stem is triangular, having three distinct sides. The flower heads are an umbel, a simple inflorescence with branches radiating from a common point, produced at the top of the plant stem. The branches of the inflorescence have small spikes, are yellow or brown in color and have one or more leaf-like bracts emerging from the base. The root system is shallow and fibrous, often producing small nut-like tubers that serve as food storage organs. These small tubers can sprout and form new plants. The plants also spread by rhizomes, or underground stems, which enables it to move rapidly throughout a lawn or landscape.
Controlling yellow nutsedge is difficult because each plant develops several small root tubers that will generate new plants. Plants are triggered to begin developing root tubers according to day length, making hand pulling most successful if started before June 21st- long longest day of the year. Determined homeowners willing to hand pull all of last year’s mature plants as soon as they start to grow this spring, then weekly recheck infestations throughout the growing season and pull any new emerging plants as soon as they are seen, and before they have the time to develop root tubers, can eventually get this weed under control. However, if new plants are allowed to mature and develop tubers before being pulled, then hand pulling will not provide adequate control.
In areas of heavy yellow nutsedge infestation, chemical control may provide the only viable option. Common grass and broadleaf herbicides will not control yellow nutsedge. Specialized herbicides for controlling sedges must be used. The most effective herbicides currently available for yellow nutsedge control are Sedgehammer (halosulfuron) and Basagran (bentazon). Several applications of herbicide will normally be needed to provide control. Success in controlling yellow nutsedge with a herbicide depends entirely on carefully reading and following label directions. When applying herbicides, avoid mowing three to five days before and after treatment. To ensure adequate herbicide absorption, do not water the lawn for at least 24 to 48 hours after product application. Applications should ideally be initiated in the late spring/early summer when the nutsedge is young, actively growing, and is most sensitive to herbicidal control. Once this weed matures, control is difficult regardless of the treatment schedule.
Sarah Browning is a Horticulture Extension Educator with the University of Nebraska – Lincoln Extension. She can be contacted by phone at 727-2775: by mail at 1206 W. 23rd Street, Fremont, NE 68025: or by e-mail at sbrowning2@unl.edu
