Plant Taxonomy of Wild Violets:
Under the deceptively simple heading of "common" or "wild" violets lies a wide array of plants. Plant taxonomy lists Viola sororia (synonymous with Viola papilionacea) as one of them, and since it is the one most likely to be encountered as a lawn weed, I'll use it as an example here.
See "Types of Violas" below for more species information. To jump right to control information, scroll down to "How to Get Rid of Violets" below.
Characteristics of This Common Lawn Weed:
Wild violets are best known for their namesake violet-blue flowers, although the blossoms do occur in other colors, as well, as you can see from the picture of a white type on this page. Markings of a different color are often present, adding further beauty to this classic flower.
The foliage is more or less heart-shaped but may also taper to a fine point; the surface of the leaves is waxy. The plants commonly grow to be about 4-6 inches high, although, depending on type and conditions, they may grow taller than that. They have a fibrous root system.
Where Wild Violets Grow:
Sun and Soil Conditions Favored by Wild Violets:
Because wild violets have pretty flowers, which bloom early and often, not everyone regards them as a type of weed, even when the landscaping area that they have chosen to call home is the lawn. Many homeowners, whether because they want to avoid herbicide use, don't wish to put any more effort into weed control than is deemed necessary, or simply crave a more natural landscape design, choose to let these wildflowers grow as they will (and may even enjoy their presence).
Moreover, they are edible weeds, as both the flowers and the leaves can be eaten. Young leaves are preferred. The taste reminds one of nuts.
Medicinal qualities are also on their resume. According to Henriette's Herbal, "The salicylic acid found in all parts...is an active disinfectant and tissue solvent and can be applied externally to soften hard skin, corns and warts. It is also fungicidal."
But Do They Draw Wildlife?:
How to Get Rid of Violets:
Now to the subject many of you have been waiting for: wild violet control. It is difficult to eradicate them. Even if you keep them from going to seed, the fact is that some types can spread via stolons or rhizomes.
When trying to get rid of violets growing in a flower bed, some people spray Roundup (glyphosate) on them. But this assumes that the weeds are sufficiently isolated from other plants (since Roundup is non-selective) and that you're not an organic gardener. Another option is to dig them up. Understand, however, that new plants will spring up from the tiniest bit of root left behind in the soil. That means two things if the infestation is considerable:
- Lots of holes
- You'll probably have to repeat your eradication efforts, as you're bound to miss something
As problematic as that sounds, trying to kill them when they're growing in the lawn is even worse. For one thing, all the holes would leave your lawn looking like a moonscape. Moreover, you can't employ mulch as an ally when attempting to control violets that have become lawn weeds.
Unfortunately, that means that, if you're committed to killing violets in your lawn, you may well have to resort to using an herbicide. Products that contain triclopyr are recommended (unless your lawn is composed of bermudagrass). One such herbicide that is readily available at home-improvement stores is Weed-B-Gon Chickweed, Clover & Oxalis killer. Expect to have to follow up with repeat sprayings.
The optimal time to spray with the triclopyr is autumn. That's when plant foods are vigorously traveling down to the root system, as the plant prepares for winter. Send triclopyr along for the ride, and you'll be able to inflict some damage. Very likely, this one application of herbicide will not kill the violets outright, however, so you might want to follow up next year in spring and then again in fall (as needed).
Because of the waxy coating on the leaves, some advise mixing a surfactant into the herbicide before spraying to reduce surface tension. There are commercial surfactants you can buy, such as Spreader Sticker. But as GardenLine host Randy Lemmon explains, you can save money by mixing in dish soap, instead. "The normal dose is about a tablespoon per gallon of spray," says Lemmon.
Types of Violas:
It is often difficult for the non-expert to identify the various wild violets, in such a way as to distinguish one definitively from another. Part of the problem in identification lies in the fact that the specimen in front of you at any given time may well be a natural hybrid plant.
Here are some examples of wild violet species:
- Viola odorata
- Viola blanda
- Viola canadensis
- Viola rotundifolia
But it doesn't end there. Some violas are landscape plants with which you are probably quite familiar (even if you call them by a different name):
- Johnny-jump-ups (Viola tricolor)
- Pansies (Viola x wittrockiana)