I also have many ants I have used poison that come in a big bag from places like home depot and Sams. I think diazione or something like that which I spread in a ring around where i do not want them like on my my deck, where most of my plants are in pots, or around the house that seems to help. But when I see a rather large hill I usually pour some bleach on it and that usually solves the problem. I do not think the bleach would be good in the beds but it seems to take care of the one that are on the outside and keeps from moving any closer.
