Several species of violet (Viola species) are native to Iowa. Violets usually grow in colonies and can be found in a wide variety of habitats ranging from dry, rocky prairies to moist woodlands.
Violets are low-growing, clump-forming plants. Most violet species have heart-shaped leaves. They typically bloom in spring (April to June). Flower colors include nearly white, yellow, blue, and purple. A few are bicolored. Each flower is composed of an upper pair of petals, two side petals, and one lower petal. The lower petal acts as a "landing pad" for pollinating insects. The fruit is a small capsule which splits into 3 parts at maturity.
Violets have also adapted to landscape sites. They are common weeds in lawns, especially in shady areas. Violets are difficult to control in turfgrass areas. Probably the best way for a home gardener to control a small infestation of violets in the lawn is to dig them up. The most effective herbicide compound on wild violets is triclopyr. Triclopyr is the active ingredient in Ortho Weed-B-Gon Chickweed, Clover, and Oxalis Killer for Lawns and several other products. Apply broadleaf herbicides in early fall or spring when plants are in bloom. Multiple applications are usually needed to control wild violets.