I had an an problem and aphid problem. 'Terro' ant baits can help control them. Try to find where the ants are getting in and put the trap there to keep them from getting near your plants. Put several of them out and it they will usually handle them. If there are several ant colonies, and there usually are, the traps may not kill them all, but they will at least keep them from your plants.
To put a quick stop to them on the plant wrap some blue painters masking tape around the base of the stem and paint it with tanglefoot. the ants get stuck in it and the painters tape easily peels off the stem leaving no damage.