What Will Kill Dandelions?

As a landscaper, I am often asked what will kill dandelions. This weed attracts so much attention because its bright yellow flowers become an eyesore on an otherwise lush green lawn. Then the flower turns into an ugly, fuzzy, round, seed ball that scatters in the wind. The scatters seeds enable dandelions to spread fast and easily.

Description of Dandelions

Dandelions are a perennial broad-leaf weed. The leaves are dark green, scalloped, and form a rosette growing close to the soil surface. Its large yellow flowers turn into puffy seed head heads when the seeds are ready to be released. The taproots are thick and long, growing to a length of 20 or more inches.




Control of Dandelions

To get rid of the plant, the entire root must be eliminated. Manually digging it out is a futile measure because any remnant of root is capable of forming a new plant.

The only practical control methods are the use of chemicals and practicing proper lawn maintenance.

1. Chemical Control

Dandelions grow best in spring and fall. Chemical control is most effective when this weed is a postemergent seedling. So the best timing for treatment is in the mid-spring and early fall.

  • Dandelions In Lawn - What will kill dandelions in your lawn is a systemic selective herbicide. The term, selective herbicide, means it will kill the weeds, not the grass. 2,4-D or MCPP are the most effective herbicides for this purpose. Garden centers sell it under different brand names such as Speedzone, Momentum, Trimec, and Trimec Plus.
  • Dandelions in Plant Beds, Patios, Sidewalks - What will kill dandelions best in these other locations is a nonselective herbicide. The term, nonselective herbicide, means it will kill any plant it touches, not just dandelions. Garden centers sell nonselective herbicides under many brand names. The most common brand name is Roundup, whose main ingredient is glyphosphate. This chemical causes weeds to stop producing proteins and they starve to death in 7 to 10 days.

Spray dandelions on a windless day when temperatures are higher than 60 degrees, but less than 85 degrees Farenheit.

If you get tired of battling weeds or don’t want to be exposed to pesticides, have a local lawn treatment company do it. I like how you can sign up online for a free estimate.

2. Proper Lawn Maintenance

Since dandelions thrive on thin weak turf, a good preventative measure is proper lawn maintenance.

  1. Mow high and mow often. Mowing high means keeping your grass on the longer side of its optimal height. This keeps the soil cooler and provides shade that restricts the growth of annual weeds. Weed seeds on the soil surface need the heat of the sun to flourish. Scalping your lawn is an open invitation for weeds. Second, once weeds have already invaded your lawn, frequent mowing will keep them in check. A weed can't form seedheads when its topmost growth keeps getting lopped off.
  2. Fertilize at the correct times. The goal is to feed your lawn, not your weeds. Cool season grasses should be fertilized in early spring and late fall. Fertilizing cool season grasses in the heat of the summer will only promote more weeds. Warm season grasses should be fertilized at the height of their growth period in the summer. Avoid feeding in the cooler spring or summer when the weeds are likely to emerge.
  3. Water deeply and infrequently. There are weed seeds hiding out in your lawn just waiting for the right conditions to emerge. Those seeds grow best when kept damp with light frequent watering.
  4. Reseed in the Fall. The fall is the best time to reseed for several reasons. Grass has nine months to get its roots deep and to get more established before facing the summer heat. It has a better chance surviving than grass planted in the spring. In the North, crabgrass and other weeds complete their life cycles in the fall and die out. So they aren't there to compete with the new seedlings for space, water, and soil nutrients.




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