Nutsedge Facts & Control

Introduction #

Yellow nutsedge (Cyperus esculentus) is a troublesome, difficult-to-control weed that is often found in turf areas (Figure 1). It is also called chufa, nutgrass, or watergrass. It is important to remember that yellow nutsedge is not a grass or broadleaf weed, but a sedge. Understanding this plant’s biology makes it easier to know how to best control it. This publication describes the life cycle and identification of yellow nutsedge and recommends cultural and chemical management options for homeowners.

Life Cycle and Identification #

Yellow nutsedge is a perennial plant that reproduces primarily by small underground tubers—called nutlets—that form at the end of underground stems—called rhizomes (Figure 2). A single plant can produce several hundred of these tubers during the summer. Yellow nutsedge can also spread by rhizomes (Figure 3). Yellow nutsedge produces a seedhead when unmown, but its seeds rarely germinate.

Yellow nutsedge actively grows during the heat of summer when cool-season turf grows more slowly. Yellow nutsedge typically emerges (germinates from tubers) in Indiana in late April or May (a few weeks after crabgrass germinates) and grows actively until the first frost in autumn. A frost will kill the plant’s aboveground portion but the tubers will survive and overwinter in the soil. Dormant tubers can germinate and emerge throughout the following season or survive in the soil for more than three years.

Yellow nutsedge is most noticeable in summer because its leaves grow more rapidly than the turf during the hottest summer months (Figure 4). During spring and fall (when it is cooler) nutsedge growth is slower and not as easy to spot in turf.

Yellow nutsedge can be identified by the triangular shape of its stem. You can feel the shape by rolling the stem in your fingertips. Yellow nutsedge leaves are arranged in groups of three (three-ranked), which also distinguishes it from grasses (Figure 5). The leaves are light green to yellowish, and each leaf has a long, tapered tip. Each leaf also has a prominent midrib and has a slick, shiny, or waxy appearance. While many grasses (such as crabgrass) have hairs on the leaf blades, yellow nutsedge does not. Yellow nutsedge will produce a golden seedhead, although the seedhead seldom forms in frequently mown turf.

Yellow nutsedge is a problem in many agricultural fields and in lawns converted from farmland. It is also a troublesome weed in horticultural and nursery crop production. Yellow nutsedge tubers can easily be spread by soil (topsoil or fill dirt) from one area to another during construction. Additionally, people and equipment can spread yellow nutsedge any time they move soil while planting or dividing ornamental plants in the landscape.

The best method for controlling yellow nutsedge (and other weeds) is to grow a healthy, dense, vigorous stand of turf that can compete with weeds. Encourage dense turf stands by following proper turf maintenance practices, including fall fertilization, proper irrigation, frequent mowing at the proper height, and over-seeding as needed.

Yellow nutsedge is most problematic in turf that is mown too short, and it thrives in areas where soils remain moist from poor drainage or over-watering. However, yellow nutsedge can also be a problem in well-drained areas, especially thin turf.

If only a few yellow nutsedge plants are present, hand pulling will help eliminate the weeds but will not remove the tubers in the soil. Several weeks after pulling yellow nutsedge, check the area to see if the plants have regrown from the tubers. For yellow nutsedge in landscape beds, it is best to remove the entire plant (including the root/rhizome system) by digging around the plant’s base. This will help ensure that you will not get regrowth from the nutsedge’s underground rhizomes.

Control with Herbicides #

Herbicides may be required when large patches of nutsedge are present in the turf. The traditional herbicides used to control dandelions (Taraxacum officinale) and crabgrass (Digitaria spp.) are ineffective since yellow nutsedge is a sedge and not a broadleaf or grass. Herbicides that contain halosulfuron (Figure 6) or sulfentrazone (Figure 7) are recommended for yellow nutsedge control.

Regardless of herbicide selection, yellow nutsedge is a difficult-to-control weed that may require multiple herbicide applications. Follow label directions about when to make follow-up applications, if needed.

Steps for Successful Herbicide Application: #

1. Read and follow all directions on the herbicide label.
2. Do not mow one or two days prior to or following the herbicide application.
3. Treat the area with the proper rate of herbicide and volume of water listed on the product label. Do not apply the herbicide if the turf is stressed due to drought or high temperatures (≥90°F).
4. Six to ten weeks after the first application, repeat steps 2 and 3 if the yellow nutsedge has recovered or regrown from tubers.

Summary #

In summary, yellow nutsedge is a problematic weed and is difficult to control with nonchemical options. Many herbicides are available for sedge control, but proper herbicide use and application timing are critical to optimize control. For best results, apply herbicides prior to tuber production. The most common mistake is applying herbicides too late in the season after yellow nutsedge has begun spreading by rhizomes and producing tubers. To be effective, implement a sedge control program early in the season and continue for more than a year to reduce tuber populations in the soil and prevent the spread of this problematic weed.