Timing is critical so that the herbicide is transported to the roots as plants go into senescence.
You will be provided with 27% glyphosate (Aquamaster or Rodeo), approved for wetland use. This is appropriate for stem filling only; it must be diluted if used as a foliar spray.
For patches with large canes, at least ¾” diameter: Stem Filling
For large, previously cut patches or plants with stems too small to fill, apply as foliar spray:
For knotweed in sensitive areas that cannot be stem filled: Glove Wiping
*(The Rockport Transfer station is now allowing large canes to be placed directly in the incinerated trash bins. It is still a good idea to bag the small pieces so they do not escape.)