Invasive flowering weed in lawn. What is it and how to erradicate!?

Asked April 10, 2020, 4:34 PM EDT

Hello, The attached photo is of a blueish flowering weed in my neighbor's lawn and she has no idea how to get rid of it. It seems to be spreading, and I don't want it in my lawn! Help!

Clackamas County Oregon

1 Response

Directly from Missouri Botanical Garden:

“Violets, Viola spp., are often found in shady areas of thin turf where the soil is moist and poorly drained. Some people find them troublesome, but others welcome their pretty bluish-lavender flowers in spring. Violets are perennial, meaning they will come back year after year and given the opportunity will spread via seeds.

Integrated Pest Management Strategies

1. Live with the violets. A few violets can be attractive. All you may need to do is improve the health of the lawn so the lawn can better compete.

2. Hand pull or dig violets. Small areas or scattered plants can be hand pulled or dug. A good followup strategy is to then improve the health of the turf so new plants will be choked out.

3. Spot treat. If you have a few scattered plants or a few confined areas, spot treat with an herbicide such as glyphosate (Roundup, Kleenup). THIS CHEMICAL WILL ALSO KILL GRASS so direct the chemical only on the individual weeds or use to kill areas where the soil will be improved and grass replanted. Spot treating can also be done with the herbicide, triclopyr (Turflon). It will selectively kill violets and not damage the grass. After killing the violets, it is necessary to improve the health of the lawn or the problem will just reoccur.

4. Use chemical herbicides. If large areas of lawn are affected, violets can be killed selectively with Trimec (a combination of 2,4-D, MCPP and dicamba) or triclopyr (Turflon). Turflon is the herbicide of choice for the lawn industry, but Trimec is more readily available. Two or more applications may be needed. Improve the health of the lawn to reduce the reoccurrence of violets. If large areas of lawn are in poor condition, it is best to kill the entire lawn in late summer, improve the soil, and reseed in the fall.

5. Improve lawn maintenance. Once the immediate problem is under control using one of the methods above, the only long-term solution is to improve the vigor of the grass so it will choke out new plants before they become established. Steps may include reducing the amount of shade, improving soil drainage, watering turf during dry spells, and selecting grasses well adapted to local conditions. In general the turf-type fine fescues will compete better than Kentucky bluegrass. Mow high to help shade out weeds. It is especially important not to scalp shaded areas by mowing too low.

Organic Strategies

Strategies 1, 2, and 5 are strictly organic approaches.”

Added Suggestions

If using an herbicide:

  • Read and follow the manufacturer's label.
  • Wear Personal Protective Equipment (PPE) to avoid skin contact and breathing mist from the herbicide.
  • Add surfactant or a tablespoon of dish soap to the weed killer. The waxy leaves of wild violets can cause the herbicide to run off, but the surfactant will help it stick and be absorbed
Spot treat individual wild violet plants with the herbicide mixture, thoroughly wetting all the leaves.

There are several reasons for tolerating wild violets in the lawn:

  • Because wild violets have pretty flowers that bloom early and often, not everyone regards this plant as a weed.
  • The plant is friendly to bees and other pollinators.
  • It makes for a low-maintenance lawn.
  • It avoids the use of herbicide. Wild violets and other wildflowers can be a great ground cover in moist, shady areas where the grass is difficult to grow.
  • It is conducive to natural landscape design; as wild violets are a native species.
Wild violets are also edible weeds. Both the flowers and leaves can be eaten, and young leaves have a pleasant nutty taste. Plus, some people use wild violets medicinally. I enjoy wild edible flowers spread atop green salads. Also, wild violets can be candied; very impressive when used to decorate cakes. Here is a link on how to make candied violets.
  • Note that it is the fact that the candied flowers are dried/dehydrated that safely preserves them (as much as it is the sugar) that allows them to keep in a tightly closed container.

Good luck and happy gardening.