Control yellow nutsedge before June 21

June 2, 2017

Lincoln, Neb. — A grass is a grass unless it’s a sedge. And to start ridding yellow nutsedge in your lawn and landscape, homeowners should act before June 21.

Spreading mostly from underground rhizomes and tubers, yellow nutsedge is common, persistent and troublesome. Also called nutgrass, the fast-growing perennial makes turf nonuniform and can overtake lawn grass. In landscapes, rock mulches and even landscape fabric don’t suppress it. Common in wet soils, it’s also problematic in drier sites.

“It’s tougher than goosegrass, tougher than crabgrass,” said Cole Thompson, Nebraska Extension integrated turfgrass management specialist. More than 150 sedge species can be found in Nebraska, Thompson said, none as difficult to control as yellow nutsedge.

Yellow nutsedge leaves are yellow-green, somewhat waxy, and thicker and more rigid compared to most grasses. Leaves are produced in groups of three, and later in the season, yellow-brown spikelets cluster at the top of stems. Sedge stems are solid and triangular: roll the stem between your fingers and you can feel that “sedges have edges.”

If you suspect yellow nutsedge in your lawn or landscape, Thompson urges homeowners first to accurately identify the problem. Nebraska Extension offices can help with weed identification and treatment options.

Typically in Nebraska yellow nutsedge emerges in mid- to late May although this year it was noticeable by mid-April. Hand-weeding or herbicide application is best done as soon as yellow nutsedge is distinguishable, and before the longest day of the year, June 21. That’s when the plant initiates new tubers, up to 8 to 14 inches underground. Patches of the weed can grow to 10 feet in diameter.

When yellow nutsedge is in the lawn or turf, follow these practices:

-        mow frequently at 3 to 3.5 inches, to give turf a competitive edge;

-        irrigate deeply and infrequently;

-        aerate to reduce soil compaction; and

-        increase shade by planting larger shrubs and perennials in landscape beds.

For postemergence control in cool-season turfgrasses and buffalograss, Extension recommends products with the following active ingredients, based on the last four years of research:

-        sulfentrazone (Dismiss), root absorbed, may provide control in turf where herbicide more readily reaches the soil; provides preemergence control of germinating tubers;

-        imazosulfuron (Celero);

-        halosulfuron (SedgeHammer), has the best control in turf sites as it is absorbed through the leaves; and

-        mesotrione (Tenacity), provides preemergence control of germinating tubers.

Always follow label directions and “try to begin control strategies early in the season,” Thompson said, adding that a subsequent application in mid-July may improve control. Tubers will still send new shoots in subsequent years, although with diligent pulling, spraying and turf reestablishment, he said yellow nutsedge can eventually be eliminated.

Yellow nutsedge is documented in 48 US states, including Alaska, as well as Canadian provinces.

Current University of Nebraska-Lincoln yellow nutsedge research is focusing on its biology throughout the country, to better understand its diversity and control.

For more turf information, see http://turf.unl.edu/turf-info

Cole Thompson
Integrated Turfgrass Management Specialist
Nebraska Extension
402-472-5159
cole.thompson@unl.edu
Writer: Cheryl Alberts - Pesticide Safety Education Program
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