Image Kills Nutsedge is a selective, post-emergent herbicide that can be used on southern turf grass and selected ornamentals. It can be applied year-round. Its patented one-of-a-kind formula works by inhibiting the weeds' process of photosynthesis, which essentially starves them to death. Growth inhibition begins within a few hours of application, with yellowing occurring 1-2 weeks later. Full results are seen within 3-5 weeks. If necessary, a second application can be made after 6 weeks. Image Kills Nutsedge targets tough southern weeds including purple and yellow nutsedge, henbit, crabgrass, dollarweed, and dandelion. For established lawns only. Not for use on cool season grasses.