My cardoon has resident ants
? Is this normal as none of the other plants close by are affected
The plant is healthy and growing
? Do they just like cardoons
You need to water the plants well to make sure they are not bone dry at the roots and then leave the rest to nature. Predators will move in and deal with the aphids, altho the ants will try and protect them against ladybirds and their larvae, lacewings and others.
It will all balance out if left well alone.
"We don't stop playing because we grow old; we grow old because we stop playing." - George Bernard Shaw