At some point during every growing season, turfgrass professionals are faced with a familiar foe: nutsedge. The warm-season perennial weed emerges in mid- to late-spring in most parts of the U.S. and actively grows in warm weather. In southern states like Florida, nutsedge is a persistent and year-round problem.
Nutsedges are often referred to as ‘grassy’ weeds, but they are not truly grasses. In fact, purple and yellow nutsedges, as well as Kyllinga species and annual sedge, are in the Cyperaceae family. Once you’ve properly identified it, you can establish an effective control program.
- Though it will grow in drier areas, nutsedge prefers moist and saturated soil conditions.
- Typically, has a glossy, light-green leaf color and veined triangular stem. If you run your fingers along the stem, you should notice a sharp edge because “sedges have edges.”
- Nutsedge has a fibrous root system, extensively branched tubers, and rhizomes.
Yellow vs. Purple Nutsedge
- The seed head is the best way to identify the type of nutsedge, though keep in mind that seed heads may not be present in a managed turfgrass stand due to frequent mowing.
- The leaves are subtly distinct between the two species: yellow nutsedge leaves gradually taper to a sharper point; while purple nutsedge leaves abruptly taper to a point.
- Tuber systems differ between the species: yellow nutsedge tubers do not connect in chains; while purple nutsedge tubers are connected in chains.
Nutsedge Cultural Control
- As with every weed, a well-maintained, healthy, actively growing turfgrass is the number one way to manage nutsedge. This includes proper mowing, irrigation, fertilization, and cultivation.
- If nutsedge infestation is present, check irrigation systems to make sure the turf is not getting overwatered or there aren’t any excess overlaps between irrigation heads.
- Increase turfgrass mowing heights during stress periods. This is very important for cool-season grasses in summer when the nutsedge is most competitive against the desirable turfgrass.
Nutsedge Chemical Control
- Pre-emergent herbicide options are available; however, post-emergent herbicides are typically required for acceptable control since nutsedges are perennial weeds.
- Herbicide application timing is critical for effective nutsedge control. It is important to apply herbicides soon after nutsedge emergence in the spring. This application timing limits the number of rhizomes and tubers the plant can produce to further spread. Waiting until mid-summer to treat for nutsedge gives the plants time to grow more rhizomes and tubers to re-grow and survive herbicide applications.
- Typically, multiple herbicide applications are required for season-long nutsedge control.
- Herbicide active ingredients for nutsedge control include, but are not limited to: pyrimisulfan, flazasulfuron, halosulfuron, sulfentrazone and trifloxysulfuron.
- It is important to rotate or tank-mix herbicide modes of action to avoid herbicide resistance.
- Best Management Practice for Yellow Nutsedge Control
- Best Management Practice for False Green Kyllinga Control
- Herbicide Application Programs and Weed Management Plans to meet the specific needs of your region, while managing resistance