Yellow nutsedge is a perennial weed with three angled stems, long grass -like leaves, and yellowish green foliage with tiny tubers at the ends of their underground stems. The tubers drop off the stems, sprout, and seedlings emerge from May until mid-July. Dormant tubers could possibly remain viable in soil for ten or more years and are easily spread by cultivation.
Nutsedges are a problem in lawns because they grow faster, have a more upright growth habit, and are a lighter green color than most grass species, resulting in a nonuniform turf. The time to control this weed is the end of May until the end of June. Once the tubers drop off of the underground stems, killing the plant does nothing to prevent the tubers from over wintering and sprouting next year.
Sedgehammer is a powder that is mixed with a gallon of water and sprayed on nutsedge directly. It will not harm the existing turf grass.
Nutsedge Killer by Ortho is a ready-to-spray, 24oz. bottle which can be sprayed directly on the lawn without affecting turf grass.
Sedge Ender by Bonide is available in a 16oz. liquid concentrate that will treat 5,800 sq.ft. It must be applied twice, with the second application thirty days after the first.