Wild violets are often among first flowers to bloom in the spring. They are a perennial, coming back stronger and more plentiful every year. If you are not a fan of these wild beauties, you will have to aggressively work to rid them from your yard.
Dig up the plant in the spring with your hand trowel. There will be a rhizome below the soil that will continue to grow and produce new plants until you remove it. Some of the rhizomes can clump together and form mats underground that will crowd out any other plants. Remove every one you can find or they will come back, vigorously.
Watch for any signs of the little leaves and spray them each individually with a wide-leaf herbicide. It usually takes a week to work. Typically, the chemical should be applied midday, after dew has dried.
Cover the area with a layer of landscape fabric if its heavily invested. Pile on a few inches of soil or mulch to suffocate the violets. If any little leaves make their way up, spray them with herbicide again. Plant your garden plants as usual.