Yellow and or purple nutsedge can be very tough weeds to manage in southern lawns due to their rapidly spreading perennial tubers. Sedges can be readily identified by their triangular stems, shiny waxy leaves and hard basal tubers. Yellow nutsedge can be distinguished from purple nutsedge by its long gently tapering leaves, tubers at ends of whitish rhizomes, and yellowish-brown seed heads at the ends of triangular stems. Leaves of purple nutsedge are shorter with tips abruptly coming to a point, having chains of tubers, and seedheads with a purplish tint.
While there are several pre- and post-emerge herbicides that do a fair job of controlling yellow nutsedge purple nutsedge is much harder to control. Since the introduction of the sulfonyl-urea type herbicides into the turf market there are products available now that can be very effective in controlling these and several other sedges and sedge type weeds post-emerge with little to no injury to warm-season turf species. With use rates being extremely low and toxicity levels for mammals very safe make these products favorable for home lawns. Trifloxysulfuron (Monument) is labeled only for bermudagrass and zoysia lawns while halosulfuron (Manage, Sedge Hammer) and sulfosulfuron (Certainty) are labeled for centipede, St. Augustine, Bermuda and zoysia lawns. Dismiss South is another product containing sulfentrazone and imazethpyr that can be used on most warm-season turf species except St. Augustine.
In using any pesticide, whether it being an insecticide, fungicide or herbicide always read the label carefully and thoroughly to ensure it can be applied safely to your lawn species.
Published June 18, 2012
Dr. Wayne Wells is an Extension Professor and Turfgrass Specialist. His mailing address is Department of Plant and Soil Sciences, Mail Stop 9555, Mississippi State, MS 39762. firstname.lastname@example.org