What Theo said.

If more than a few, spray them with an 8% pond rated glyphosate solution with 1 fl. oz surfactant added per gallon of tank mix. I like to add pond dye to the mix to see where I am spraying. You can spray throughout the year,, but it's most effective in the Fall when the plants are concentrating on taking nutrients down to the roots.

Any catkins that form this year I would cut off before they become mature seeds. Dispose of them in the trash.

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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).