Troublesome Weeds: Dandelion
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What weed above all else is the bane of weed management for turf managers and homeowners alike? Here’s a hint: it’s yellow.
Dandelions.
“It’s probably the weed that gets the most complaints across the U.S.,” said Dr. Jared Hoyle, territory manager and self-proclaimed turf nerd.
It’s a perennial weed that lurks in lawns and turf over winter as small rosettes of leaves. When winter turns to spring, dandelions grow from a tap root or new seedlings.
Bright-yellow solitary blossoms produce a puffball seed head — making it stand out like a sore thumb in turf and lawns alike.
“Those bright blooms are very contrasting compared to green grass, even brown grass,” Hoyle said. “I think it's one of the weeds that causes the most angst for turfgrass managers and their customers just because it’s a highly visible weed.”
What makes dandelions so challenging?
The weed’s easily recognizable white, puffy seed heads are partly to blame. A single dandelion plant can produce ten flower heads, each with about 150-200 florets. Each of those florets produce one seed, meaning one lone dandelion plant can produce up to 2,000 seeds.[1]
Hoyle said one trait that makes the weed a menace on golf courses specifically is its ability to tolerate all kinds of mowing — tall mowing, low mowing and no mowing at all — thanks to its large tap root.
Although not as common, dandelion’s tap root can reach lengths of up to 3 feet but are often between 6 and 12 inches.[2]
“They can be scalped off and grow right back,” Hoyle said. “Its effect on the playability of a course is what makes it so destructive. No player wants their ball to land on a dandelion or find their ball next to one — it would change their stroke; it would change their ball contact and even ball flight and maybe the outcome of that shot.”
How do you control dandelions?
Hoyle said it may come as a surprise, but one key to controlling dandelions is understanding the soil and environment that it is growing in.
“We probably would have never really thought about what an underlying issue could be or what was going on in the soil or in the environment or how we’re managing it, because dandelions are everywhere,” Hoyle said. “But one thing that I didn't realize until digging deeper into some of the research that was out there is that dandelions prefer high potassium soils.”
Hoyle said that if you find yourself with a high concentration of dandelions, start looking at the fertility program and always test your soil to determine the correct fertility program.
“There are a lot of options out there, but a multilevel approach is definitely most important, preventatively on top of a post cleanup type application,” Hoyle said.
Preventative applications slow down seed movement, as well as slow down anything that might germinate throughout the summer. But that’s only effective after preemergence applications with products that are labeled for dandelion control.
Dimension® and Gallery® specialty herbicides will prevent dandelions from emerging, according to Hoyle. Dimension specialty herbicide offers pre-emergence control while Gallery specialty herbicide is one of the most effective tools against a wide range of broadleaf weeds including dandelion. Crew is another option that contains both the active ingredients in Dimension and Gallery and is another very effective option for both turf and ornamental beds. Not to mention it is a granular product.
Once the life span of your preemergence herbicide is out, the window for new emergence is opened.
That’s where Defendor® specialty herbicide comes in, Hoyle said.
Defendor specialty herbicide is a postemergence product effective in the fall and early spring, and performs very well in cold weather — a time when other postemergence herbicides aren’t as effective. It saves time and money by controlling high-anxiety weeds, such as dandelion, before they bloom, reducing callbacks and minimizing complaints.
“Some of these older chemistries that we’ve typically used would have to be soaked up by the foliage of the dandelion. Defendor has some root activity, so say the leaves have been scalped off, or the weed is underneath that turf canopy, Defendor can be absorbed through both the foliage and the roots, giving it excellent control.”
Dandelions have been a menace on turf and lawns since what seems like the dawn of time, and Hoyle said they’re not going anywhere anytime soon, so keep your toolbox stocked with tools to execute a multilevel approach.
“It’s always one of those weeds that I would prepare for having just because of the vast amount of plants and seeds that are out there,” Hoyle said. “That ounce of prevention is definitely worth a pound of cure.”
[1] https://gardens.duke.edu/sites/default/files/Duke%20Gardens%20-%20Meet%20a%20Plant%20Dandelion.pdf
[2] https://hort.extension.wisc.edu/articles/dandelion-taraxacum-officinale/
State restrictions on the sale and use of Defendor® and Dimension® apply. Consult the label before purchase or use for full details. GameOn® is not registered for sale or use in all states. Contact your state pesticide regulatory agency to determine if a product is registered for sale or use in your state. Always read and follow label directions.
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