Alligatorweed is actually a aquatic weed and normally only found on over watered lawns. Mowing actually spreads Alligatorweed by vegetative propagation. Recommend Aquatic chemical suppression include Glyphosate and 2,4-D which is one the herbicides in 3 Way. However Triclopyr is listed as a control. Once the Alligatorweed hits land 2,4-D will control it. Remember Alligatorweed grows as a Emersed plant or under water but does break the surface.
You can lead a Donkey to water but you can't make the Jackass Drink
"As Americans you have the right to be stupid." John Kerry
"Life is tough, but it's tougher when you're stupid.” John Wayne.