How to Kill Dandelions

Dandelions can completely take over your lawn. Learn how to kill dandelions and prevent them from coming back.

What Are Dandelions

Dandelions are an herbaceous perennial plant with yellow flowers.

Despite their bad rap, dandelions have many uses. For starters, they are a great source of food for bees and other pollinators, especially early in the season before most other flowers have bloomed.

Dandelions also have medicinal uses, and believe it or not plenty of people eat them. Everything from the flower to the root is edible.

While dandelions have many benefits, they can be a nightmare lawn weed for those of us who take pride in having a green, manicured lawn.

Dandelions Life Cycle

During the winter, dandelions go dormant.

In early spring, they are one of the first plants to wake up. In May and June the flower blooms are most intense. During the day flowers are wide open and bright yellow. During the night flowers close and are not as noticeable.

As flower blooms start to fade, the plant focuses on seed production. Eventually, instead of yellow blooms you’ll notice fluffy white seeds that will be swept away with the wind.

These seeds germinate and new plants emerge.

During the hot summer months dandelions are less active and can even go dormant for a short period.

Once soil temps cool off heading into fall they wake back up. It’s normal to see another cycle of flowering followed by more seed production during the fall months. This fall cycle is not as intense as the spring.

Why Are They Tough to Kill

Their overall hardiness and ability to spread an abundance of seed can make dandelions tough to control.

Unlike a lot of broad leaf weeds, dandelions don’t die at the end of the growing season. Instead, dandelions are perennial meaning they go dormant during the winter months but will reappear in the spring.

Dandelions are also tough to kill because of their long tap root. A single tap root anchors deep into the soil making manual removal difficult. It’s very hard remove the full root of a mature plant with your bare hands, and if you don’t remove the whole root then the plant will likely survive.

1. Dandelion Puller

Using a dandelion puller is a great, organic way to remove dandelions. These puller tools get deep into the ground where the tap root is and they yank out the whole plant including the root. Puller tools are a great option if you have a low to moderate weed problem. Their main benefits are they are safe, eco friendly, and best of all you get instant results.

2. Spot Treat with Lawn Safe Herbicide

Spot treating means spraying each individual plant directly with a liquid herbicide.

* Using a product like Ortho Weed B Gone is a great choice if you have a small to moderate problem. This product is also useful in controlling other broad leaf weeds such as crabgrass. It’s also the product I recommend in my simple lawn care program which uses only 3 products.

* Another option which is best for warm season grasses, is Image Southern Lawn Weed Killer. The front label says it’s safe to use on St. Augustine and Centipede Grass but it’s also safe to use on other warm season grasses such as Bermuda, and Zoysia. This product is a concentrate and gets mixed with water, in a tank sprayer. Follow the label for mixing ratios.

* Tenacity (active ingredient Mesotrione) is another lawn safe herbicide that will kill dandelions as well as other broad leaf weeds. This product is a concentrate and requires mixing with water in a tank sprayer. This is a better choice for cool season lawns since Tenacity can damage some warm season lawns, especially Bermuda grass.

Tenacity is a great choice if you are planning on seeding your cool season lawn. Unlike most post emergent herbicides, you don’t have to wait over a month to seed after applying. In fact, you can seed and treat weeds with Tenacity on the same day and it won’t negatively impact seed germination.

When spot treating don’t expect instant results. It can take 1-2 weeks for the weeds to die. It may also require a second application.

The main benefit of spot treating is it’s less labor intensive then manual removal.

3. Blanket Spraying

If your lawn has a more serious dandelion problem then it will take forever to spray each individual weed. That is when blanket spraying is a better option. Blanket spraying is when you apply liquid herbicide over your entire lawn, or entire sections of your lawn. This is usually done with a tank sprayer.

Use a liquid, lawn safe weed killer (like the ones listed above), and simply follow the blanket application instructions on the label. Once again, this will target other weeds as well without harming your lawn.

4. Hose End Weed Killer

If you require a blanket application of herbicide but don’t want to invest in a tank sprayer then you an choose to apply using a hose end sprayer.

Personally, I’m not a huge fan of hose end applications. They can be hard to calibrate and I like the consistency of a tank sprayer better. I also don’t enjoy dragging hoses around my 23,000 s/f lawn. But plenty of people swear by hose end sprayers and for smaller lawns they make a lot of sense.

Do Granular Post Emergent Herbicides Work

I’m not a big fan of granular post emergent herbicides for controlling dandelions. Once a dandelion plant is already establish you’re going to have much better results using the weed puller, spot treating, or blanket spraying.

Granular post emergent herbicide products like Weed and Feed require very specific conditions to get the herbicide to stick to the plant. Even then, these products have mixed results.

How to Prevent Dandelions

Preventing dandelions really comes down to 3 things:

1. Pre Emergent Herbicides

Unlike granular post emergent herbicides, granular pre-emergent herbicides are noticeably effective. My go to granular pre-emergent herbicides are Prodiamine and Dithiopyr.

These products need to be applied at the right time to be effective. Check out this post where I talk about pre-emergents and timing: Lawn Care Program

Just remember, dandelions are perennials. That means pre emergents will prevent new dandelion seeds from emerging, but it will not prevent the dandelions that have overwintered in your lawn from coming back.

2. Killing Existing Plants

Since mature dandelions produce seeds that eventually become more dandelions, killing existing plants is key in controlling the problem.

3. Mowing

Mowing frequently and bagging your clippings is going to help control the spread of dandelions. Mowing cuts off the flower portion of the plant, making it impossible to produce seeds. Collecting the clippings prevent the seeds from being mulched back into your lawn.