Killing Wild Violets – Tips For Wild Violet Control

Killing Wild Violets – Tips For Wild Violet Control

By: Jackie Rhoades

Controlling wild violets in the lawn may be one of the most difficult gardening problems a homeowner can face. Those pretty little plants can take over a lawn in just a few short seasons and once they take hold, nothing is as tenacious as the wild violet. Control or killing wild violets in lawn can take years.

Why is Controlling Wild Violets So Difficult?

Wild violets are cool season perennials that grow best in shady, moist soil. There are three problems with these tough little plants that make killing wild violets so difficult. Wild violets have two types of flowers — the pretty purple ones that children gather for their mothers and the plain, unopened ones that shelter beneath leaves that protect them from most types of wild violet control. The purple flowers may be sterile. The flowers beneath the leaves are not only fertile, but self-fertilizing. They don’t need to bloom to reproduce.

Thick clumps of underground stems, called rhizomes, store water so the plants can survive drought. When a gardener tries to kill wild violets in the lawn, the rhizomes survive and send forth new shoots.

Those lovely heart shaped leaves pose the third problem in controlling wild violets. The waxy coating that gives the leaves their shine also prevents herbicides from penetrating the leaves.

Killing Wild Violets

Treatments for controlling wild violets are best applied in the fall as the plants take in herbicides more easily at this time. Spot treatments with an herbicide that kills all vegetation works best for mild infestations, the downside being brown spots dotting the lawn. For broader applications, use granular herbicides. Be sure to check the label to be sure killing wild violets is listed. Concentrates applied with a garden hose attachment will damage the plants but as with most treatments, repeated applications will be necessary to kill wild violets.

The best method of wild violet control is a thick and healthy lawn. The dense roots of the grass will help prevent those pretty little devils from ever taking root.

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How to Kill Yard Violets

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Wild violets (Viola spp.) may have pretty purple or blue flowers, but these annual weeds can quickly become an eyesore when they invade your yard. If you don't control them as soon as they appear, yard violets will slowly spread through their underground rhizomes and take over more of your gardens. Use a combination of methods to kill these invaders.

Controlling Wild Violet Weeds in the Lawn

One of the most difficult weeds to control in the lawn is wild violet. This native plant may look cute and dainty, especially in the spring when it produces pretty purple flowers. But in reality it is an aggressive weed with an unusual flowering quirk that results in thick mats of leaves that can choke out your lawn.

Wild violets are very tough plants that tolerate drought. But the ideal condition for them is moist soil, which this year’s above average rainfall has provided. This has resulted in vigorous growth and spreading of this weed.

In spring, wild violets produce their well-known purple (or sometimes white, bicolored or speckled) flowers, which are often mowed off. But in summer violets can produce a different type of self-pollinating flower that stays below the leaves (or even underground) and produces seeds that are dropped in the surrounding area. These flowers will not be mowed off, allowing for a large amount of seeds to be spread. They also spread by underground stems. Using these two methods, they can eventually create dense colonies.

Wild violets can be controlled, but it does take some effort and repeat treatment. Fall is the ideal time to control wild violets as they will more readily move herbicides into the root system as they prepare for winter.

Due to their fleshy, energy storing roots, any non-selective herbicide you use must be systemic. Glyphosate (Roundup®) will work but may take 2-3 applications a few weeks apart. Non-selective herbicides will also kill any plant they contact, including grass, so protect surrounding areas with a shield of cardboard or use a brush to apply only to the violets.

Selective broadleaf weed herbicides must list wild violet on the label to be effective. Bonide Chickweed Clover& Oxalis Killer is an option, or a product containing dicamba and triclopyr, but again it may take several applications to completely eradicate established plants.

Non-selective herbicides will work, including Roundup and organic herbicides, but it takes repeated treatment to gain control as the roots can be difficult to kill.

After the existing plants in your lawn are controlled, you will need to use a pre-emergent herbicide in spring & fall to prevent the many seeds the violets have already spread from sprouting. Further suppression is gained by maintaining a thick, healthy lawn that prevents weeds from becoming established.

Wild violet is a tough to control perennial weed that will just keep expanding if nothing is done to control it. Fall is the best time of year to contro l wild violets, as it is with all weeds, a time when they take everything down to the root to store for the next growing season. Use a broadleaf killer that contains 2,4-D or Dicamba, and it will selectively kill the violets without damaging the grass. Another wild violet herbicide is called Drive (quinclorac).

Trade names with the above active ingredients are often available only to professional applicators but one found in most stores named Weed B Gon contains all three of the above active ingredients and selectively does not injure turfgrass. This is not a good time to use it however as doing so at high temperature times can injure turfgrass. Be sure and read the label for whatever you do use. It will likely take more than one season to bring down wild violets permanently. Fall after the first frost on a sunny afternoon would be the ideal application time.

Chemical Controls

Wild violets should be treated in the fall, when the plants are actively growing and air temperatures are less than 90 degrees Fahrenheit. Among the more effective chemical treatments are triclopyr products and combinations of 2,4-D, MCPP and dicamba. Mix 2 to 4 tablespoons of the herbicide concentrate with 1 gallon of water to treat 400 square feet of lawn. Adding 1/2 ounce of a spreader sticker product to 1 gallon of herbicide helps it stick to the waxy leaves of the violet, improving the herbicide's effectiveness. Soak the leaves of the plants using a spray bottle, or use a tank sprayer to treat the entire lawn according to the manufacturer's directions. Repeat the treatment in 10 to 14 days.

Precautions and Considerations

Wild violet weed control is difficult and repeat applications of the homemade weed killer may be required. The effectiveness of the homemade horticultural vinegar weed killer varies and you should consider other control options including applications of commercial herbicides containing triclopyr or dicamba.

It's best to apply horticultural vinegar or other weed killer in the fall to control wild violets because the plants absorb more of the herbicide at this time. Trying to control wild violets in the summer typically provides poor results.

Marylee Gowans has written about gardening for both online and print publications. She attended the University of Akron, graduating with a Master of Fine Arts in creative writing. In 2009, she received master gardener certification from the Master Gardeners of Summit County, Ohio.

(Not So!) Wild About Wild Violets

Q. Mike: Violets are my problem. I don't want to tear up my lawn and start over or use chemicals (which don't work anyway). What can I do to make these stubborn little weeds go away?

    ---Peter in Rockville, Maryland (PS: I found your show on the Sirius 'NPR Talk' channel and got hooked!)

We can grow grass 'OK', but for some reason we can really grow violets. The lawn is being taken over by them. Removing them individually is extremely time consuming and the weed killer my husband uses only seems to encourage them. Do you have any advice?

    ---Laurie in Severna Park, MD

I have a partially sunny front yard with decent grass, relatively few "normal" weeds, and a significant amount of violets. I keep the lawn mowed pretty high and only fertilize once a year in the spring. I heard that violets like acid soil, so I have tried over the years to regularly apply lime in the fall. I have also tried spraying several times with a strong mix of 'Weed-B-Gon', but that hasn't worked either. What else can I do?

Mike: Help me get rid of wild violets. Commercial weed killers just don't do the job.

A. No, they do not. In his classic book "Lawns", Iowa State University Professor and frequent You Bet Your Garden turf grass advisor Nick Christians, Ph.D., writes that the waxy coating on their shiny leaves makes wild violets virtually invulnerable to chemical herbicides. : "They often survive when all other weeds in the lawn have been controlled."

But that warning comes after his first sentence, which reads: "Violets have an attractive blue flower and are not always objectionable in a lawn." Now, this isn't coming from some left-leaning, tree-hugging, Miracle-Gro-confiscating organic advocate like moi. Although he popularized the use of corn gluten meal as a chemical-free, pre-emergent herbicide, Dr. Nick also uses chemical herbicides. And HE says to consider just leaving violets be.

I will add that early lawns were designed to have pretty things sprout up out of them. Clover was an integral part of early seed mixes, and a clover-free lawn was considered a sign of poor care! And many people still plant small summer-blooming bulbs like grape hyacinth, crocus, species tulips and scilla directly in their lawns. By the time the turf needs its first Spring cut, the flowers will have faded and the leaves will have absorbed enough solar energy to pop up and entertain again the following year.

So the first and best answer is to do nothing. Except maybe get over yourself.

Otherwise, our Pittsburgh listener is correct violets do thrive in overly acidic soil. They also thrive in soils that are deficient in calcium. So lime may help control their spread. But don't guess how much have your soil tested and follow the recommendations as to how much lime to apply. (Or substitute one and a half times as much hardwood ash see THIS PREVIOUS QUESTION OF THE WEEK for more details on using wood ashes in place of lime.)

Nick adds that the other aspects of proper lawn care—cutting, watering and feeding correctly for your specific turf—are equally important. That lawn in Pittsburgh, for instance, needs to also be fed in the Fall to be healthy enough to hold violets at bay.

As Nick and all of our Questioners note, chemical herbicides are especially ineffective against this pretty plant. All you're doing with that Roundup and Weed B Gon is killing frogs and toads, increasing your future risk of Parkinson's and poisoning your neighbors' well. So knock it off!

If you MUST have an artificially perfect, eco-insensitive, mono-cultural, globally warm-criminal lawn, dig up the clumps the heart/kidney shaped leaves make the plant easy to spot. Use a poaching spade so you can go deep and get all the roots. Do this in the Fall for cool-season lawns and in the Spring for warm season ones so you can fill the holes with compost and grass seed and get a nice stand of replacement turf. Or, if it's just something about the violets personally—say your mother was scared by gentian while pregnant with you—dig up the clumps and plant little Spring bulbs in their place.

Or transplant them. I LOVE wild violets, and whenever some pop up in the 'wrong' place, I just move them to an area where I want more color in the Spring or some pollination insurance. Native bees looking for summer homes will be attracted to your violets in the Spring and then hang around and pollinate the rest of your plants all season long. Or maybe you didn't want lots of flowers and fruits?

And finally, wild violets are deliciously edible. They are the heart of 'candied violets', and look and taste great adorning salads. They are also a tremendous source of rutin, a hard-to-find nutrient that strengthens capillary walls, preventing or reversing the visible effects of varicose and spider veins.

Long-time listeners know that I always tell people to harvest and eat their pansy flowers for this purpose. Well, all members of the Viola family contain rutin in their flowers and as our good buddy, retired USDA researcher and best-selling author Jim Duke, Ph.D., has explained so many times, the wild form of a plant typically contains much higher levels of naturally occurring nutrients than the cultivated form.

So stop fighting your wild violets (and Johnny jump-ups) and start eating them! You'll live longer, and perhaps more importantly, look better in a bathing suit.

Watch the video: Identifying and controlling Wild Violet