Get rid of ants

[Fred]

Have you tried those circular ant traps? They contain some kind of gel that the ants then carry back to their nest and kills of all their mates. This sort of thing...
I've no idea of their toxicity to plants but the beauty is you don't actually put the stuff on your plants at all. They're been very effective here.

We did try some in the house a few years ago, but they kept walking around them. Have not looked recently, but we're not too keen on using anything non bio.