If you have other underwater weeds in the pond that you want to keep, a light dosage of Fluridone in mid fall or early spring will knock back a lot if not all of the CLPW without affecting the other plants.

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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).