I take action over ants in two circumstances. The first is if I get them in the house and the second is if I get a nest in a pot or tub. The channels in the nest make water flow straight through the pot and its hard to keep the pot watered. Mally, ants swarm over plnts usually for one of two reasons, either its queen ant swarm day, in which case it will be over soon, or they are farming aphids on your plants. A little farming on a healthy plant won’t hurt but if there are loads then spray with soapy water.