Broadleaf SignalgrassWeeds - Learn About SignalgrassControl. Bonnie L. Grant's avatar.SignalgrassControl Methods. Getting rid of signalgrass may require a two part process. How do I control broadleaf weeds in my lawn?How does signalgrass spread?Can horses eat signalgrass? Options for controlling tropical signalgrass. For TSG control in bermudagrass, several options exist depending on costs, how quickly control is desired... Bioherbicidal control of grassweeds in turf N167. grown on a commercial potting mix in plastic pots (25 cm. diameter by 22.5 cm height) were treated, three pots per. A reduction in slender amaranth control may have resulted from a combination of reduced graminicide efficacy and interference caused by broadleaf signalgrass with slender amaranth... Signalgrass is a summer annual grassy weed that is also known as Alexandergrass or by its scientific name, Brachiaria plantaginea. According to Lima (2013), the low signalgrass stand may provide lower soil cover, requiring a longer period for total cover, and, consequently, there is a higher weed infestation. 2004. Tropical signalgrass (Urochloa subquadripara) control with preemergence-and postemergence-applied herbicides. Weed Technol. 18:419-425. Broadleaf signalgrass is a rapidly spreading, serious problem weed in Tennessee corn. Though it is often confused with large crabgrass, it is much more difficult to control with... Prevention of Broadleaf Signalgrass is less expensive and less time-consuming then trying to control it. Make sure when you seed a new area you do so with certified weed-free seeds.