I am sorry ~ that is tough. When it is an ornamental, I use ant poison. I pull the plant out of the pot and place the poison in the bottom of the container, repotting the plant. To discourage them from moving in, I sprinkle the ant bait under the pot.
Seeing as this is edible I would want to be more organic. I've not used it but heard of using something called mound drench that is supposed to be organic.
Hey , put cornmeal all over the dirt, they will take it back to the mound and when they eat it, it kills them. They can not digest the meal. That reminds me, I need to do the same here again. Thanks, Krispi