I've had two kinds of ants. One of which, I do not know the species, but they are harmless. They drink the honeydew from the spikes and new growths, and I've never seen them farm any pests. They don't bite or sting and are not aggressive.

The other kind I get in pots during the summer is fire ants. They bite and sting and leave pustules where they stung, so those are a huge problem.

What I do about this is this. I take the pots, completely submerge them in water, and place a stick or ruler or something that can act as a bridge. I place it touching the plant, and then down over the edge of the pot. If I submerge the pot without a bridge, the ants all just cluster at the top of the plant. If I place a bridge so they can escape, they will all take the bridge down out of the pot in search of dryer ground. I leave the pots submerged for about 24 hours. This has never failed me. I do this with both the fire ants and the harmless ones, simply because I do not want to be bringing ant infested pots into my house during the winter. Again, this has never failed me.

Not intentionally, but the upper areas of my bog make for very easy digging, and ant colonies aren't uncommon. But a heavy rain usually convinces them to set up camp somewhere else.