FWIW, when I sprayed mine with glyo/2,4-D (amine)/surficant mix they just died and stayed in place, even next spring they were still there. No floaters just brown and bent over.

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3/4 to 1 1/4 ac pond LMB, SMB, PS, BG, RES, CC, YP, Bardello BG, (RBT & Blue Tilapia - seasonal).