A vast genus of plants, violets (Viola spp.) are often prized for their pretty, reliable spring-blooming flowers. When violets grow where they are not wanted, they are considered weeds, as is often the case with wild violets. One such wild violet is Viola papilionacea, which thrives in U.S. Department of Agriculture plant hardiness zones 3 through 7. Like others in the viola family, wild "weedy" violets grow from underground, tuber-like structures called rhizomes, which are naturally resilient, making their eradication difficult.
Pull young violet plants by hand when the soil is moist from a recent rain or watering. Do this before they flower to stop them from spreading seed. Use a fork or dandelion weeding tool, grip the weed at the base and push down to help release it from the soil. Do not break the roots, because root fragments left in the soil will resprout. If the roots break, dig out the plants instead. Discard the violets in the trash.
Dig out violets with a spade, starting about 12 inches from the clump's center. Dig 8 or more inches deep as necessary, and cut under the center of the clump to get all the roots. Shake or brush the soil off, and sift through it to look for broken root pieces. Continue digging on the bottom and sides of the hole to look for those deep taproots that might regenerate if left behind. Discard all plant pieces in the trash.
Spray a ready-to-use herbicide listed to kill violets. Use one that contains the active ingredient 2,4-D, triclopyr, MCPP or dicamba, and is safe for the lawn or flowers growing nearby. Spray the herbicide on a dry, calm day, preferably from mid-spring to summer when violets are actively growing, but before they set seed, or in fall while they are getting ready for winter dormancy. Reapply in two or three weeks, or as instructed on the label. Reapply the herbicide again if any violets remain after six weeks.