Those are maybe spatterdock aka cow lily?? Do you have a picture of the flowers? Try treating mid to late summer when plants are actively storing 'food' products into the rhizomes. Best chemical control is using one of these herbicides: glyphosate, triclopyr, imazamox or 2-4D. Common glyphosate compounds are Rodeo, Aquamaster, Eraser AQ, Touchdown Pro, and Shore Klear Plus. Renovate 3 is a triclopyr compound and Clearcast is an imazamox compound. Since you have tried triclophyr with limited success and if you have some remaining try treating later in the season and mixed a little stronger. I have had success and prefer the glysophate products with aquatic approved surfactant(adjuvant) mixed a little on the strong side of the recommended dosage. Keep us updated on your progress so others can learn. First lets find out what they are specifically by seeing a flower picture.
Last edited by Bill Cody; 08/01/15 09:40 PM.
