Sedge grass, particularly nutsedge, is a perennial weed notorious for being difficult to control in lawns and gardens. It is often misidentified as a common grass, but its unique biology makes standard weed killers ineffective. The main challenge comes from its ability to reproduce prolifically through underground tubers, often called nutlets. A single plant can produce hundreds of these tubers, which can remain dormant and viable in the soil for years. This means the weed can reappear long after the top growth is killed, requiring a targeted, multi-faceted approach for elimination.
Accurate Identification of Sedge Grass
Before beginning any control efforts, it is important to confirm the plant is indeed a sedge and not a true grass, as their control methods differ significantly. The most reliable distinguishing characteristic of a sedge is its stem structure, which is triangular in cross-section, unlike the rounded or flat stems of turfgrass. This is often summarized by the mnemonic “sedges have edges” and can be felt by rolling the stem between your fingers.
Sedge leaves are typically thicker, more rigid, and possess a waxy or glossy appearance that is distinct from most turfgrass. These leaves are arranged in sets of three, known as a three-ranked arrangement, which is another difference from the two-ranked arrangement seen in grasses. Additionally, sedge grass generally grows faster than the surrounding turf, often sticking up noticeably above the lawn just a day or two after mowing, and it often presents a lighter, yellowish-green color.
Manual and Cultural Removal Techniques
For small, isolated patches, manual removal can be effective, provided the entire underground structure is removed. Simply pulling the foliage is the most common mistake, as this breaks the plant off above the nutlet and stimulates dormant tubers to sprout new shoots. To maximize success, moisten the soil to loosen it. Use a trowel or weeding tool to dig deep and remove the entire plant, including the attached rhizomes and nutlets.
Improving the growing environment to favor turfgrass and discourage sedges is a valuable cultural technique. Since sedge varieties thrive in overly wet or poorly drained soil, correcting these conditions is crucial. This can involve improving yard drainage or aerating compacted soil, which makes the area less hospitable to the weed. For non-turf areas, solarization involves covering the infested patch with clear plastic sheeting during the hottest part of the year to kill the tubers in the top few inches of soil.
Targeted Chemical Control Solutions
Chemical control is often necessary to eliminate larger or persistent sedge infestations because of the number of viable underground tubers. Selective post-emergent herbicides are required, as general broadleaf or grassy weed killers are ineffective. The active ingredients most effective against nutsedge include halosulfuron-methyl, sulfentrazone, and bentazon.
Halosulfuron-methyl (e.g., Sedgehammer) is highly effective because it translocates through the plant down to the tubers, which is necessary for complete kill. Sulfentrazone provides a quicker visual result and offers some pre-emergent control of emerging tubers. Apply these herbicides when the sedge is young and actively growing, typically in late spring or early summer, before the plant produces new nutlets.
For optimal results, a non-ionic surfactant is recommended to help the herbicide penetrate the sedge’s waxy leaf surface. Because tubers continue to sprout throughout the season, a single application is rarely sufficient for eradication. Repeat applications, generally three to six weeks after the initial treatment, are necessary to control new shoots emerging from previously dormant tubers.
Preventing Future Sedge Infestations
Long-term suppression depends on creating a dense, competitive turf that physically crowds out the weed. A high mowing height is an effective cultural practice, as taller turf shades the soil and prevents light from reaching newly emerging sedge seedlings. Maintaining the lawn at one of the highest settings helps the desirable turfgrass outcompete the weed.
Proper irrigation practices also play a role in prevention, since sedges thrive in wet conditions. Water lawns deeply and infrequently, avoiding light, daily sprinklings that create soggy surface soil. Addressing soil health through aeration to reduce compaction and correcting poor drainage makes the environment less favorable for sedge. Finally, ensuring the turf is adequately fertilized helps maintain density, acting as a natural barrier against sedge establishment.