Yes and no.
Ok, the bulges are part of the root system as it is related to Lilies and not a grass at all as often supposed.
Provado (terrible stuff) will not kill ants, you need a specific ant poison of that.

Thanks Ob, I will put ant powder under the pot.

Annella, if you're keeping anything in pots and they're standing on paved areas, best to have something beneath to keep them raised off the ground. Anything will do, pot feet, bits of broken tile, whatever, just to give clearance. Dust that clearance with ant powder periodically too. You might also soak the plant's roots to ensure removal of all ants and eggs before repotting into fresh compost.

Thanks Bamboo, a lot of my ant problem pots are on the front garden gravel which seems to be riddled with them this year :o)

Seems to be a big problem this year, we have had to spread Ant killing stuff all the length of out polytunnel on both side because of the number of ants in there.