Groom = cut all the stems, leaves off the tuber. I do leave the tiny leaves and stems, i.e. the ones just growing.
Feed = I lift the plant and litter, pour around 1/4 cup of osmocote in the pan, put the lily back down. Some need added litter, so I will pour some on the top of the plant.
I do nothing for the pickerel rush. The only plants in my pond fed are the lilies. Everything else only gets groomed dead stuff cut off, lily leaves removed, lotus dead stuff removed. In the spring I take a rake to the bog, remove all the stuff dead from the winter.