There are many varieties of plants called by this name, so it may be necessary to take one of the plants to your local garden center to have the plant identified.
Choose a herbicide containing triclopyr unless your lawn is planted with bermudagrass. You can purchase this herbicide at most home improvement stores.
Follow the instructions for mixing the herbicide with water if necessary. Place the prepared herbicide into a garden sprayer with a narrow spray nozzle.
To ensure the herbicide stays on the wild violet's waxy leaves, use a surfactant. Purchase a commercial surfactant, or use dish soap. Mix 1 tablespoon of dish soap with each gallon of spray in the sprayer.
In the early fall, spray every violet in the lawn with the herbicide and surfactant mix. Douse the plants thoroughly, spraying the leaves most heavily.
Since it is unlikely that just one application of the herbicide completely eradicates all the violets, spray the violets again in the spring. Douse each plant thoroughly, especially all the leaves.
Repeat the spraying every fall and spring as long as the violets are present. This is a very difficult weed to eradicate completely.