Seashore paspalum is used on golf courses in warm temperate regions, but prolific growth and seedhead development may reduce turfgrass quality. Field experiments were conducted to investigate efficacy of flazasulfuron and trinexapac-ethyl on seashore paspalum seedhead suppression, clipping reduction, and canopy height. Flazasulfuron applied from 4.5 to 27 g ai ha⁻¹ increased clipping reductions from the untreated by 22 to 75% and seedhead suppression from the untreated by 16 to 86% at 2 to 4 wk after treatment. Trinexapac-ethyl applied alone at 96 g ai ha⁻¹ provided erratic levels of seedhead suppression from the untreated, but reduced clippings by approximately 50 to 75% from nontreated by 2 to 4 wk after treatment. On several dates, trinexapac-ethyl enhanced clipping reductions and seedhead suppression from flazasulfuron compared to flazasulfuron alone. Trinexapac-ethyl exacerbated seashore paspalum injury from high flazasulfuron rates (18 to 27 g ha⁻¹) but injury never exceeded 23%. Trinexapac-ethyl reduced seashore paspalum height by 50% in unmowed areas at 16 wk. Flazasulfuron at 16 or 27 g ha⁻¹ with trinexapac-ethyl provided consistent seedhead suppression and clipping reductions ranging from approximately 70 to 95% of nontreated. These tank-mixtures have promising implications for use in seashore paspalum golf course fairways.

Nomenclature: Flazasulfuron; trinexapac-ethyl; seashore paspalum, Paspalum vaginatum Sw., ‘Sea Isle 1’, ‘Sea Isle Supreme’