Weed Killer for Dandelions

Dandelion before and after seeding

One of the first signs of spring is the emergence of dandelions in lawns, gardens and flower beds. It can often seem like no matter which methods you try, dandelions keep coming back to wreak havoc on grass and flowers. Controlling dandelions with herbicides is part art and part science, but there are effective measures that can be taken to reduce the appearance of dandelions in your lawn.

Significance

Dandelion weeds can cause problems within lawns, orchards and ornamental beds. Dandelion grows leaves 6 to 14 inches in diameter, taking over desirable species in the process. Chemical treatments are often necessary because dandelions have strong roots, and pulling them up is usually ineffective unless it is done consistently over a long period of time. Pulling or hoeing dandelions is recommended for home gardens, but it may be time consuming and ineffective for larger areas.

First Steps

Before using a herbicide in a lawn or garden, pulling up young dandelions is recommended. Special dandelion knives and tools can be purchased at home and garden stores. These tools can help to safely remove dandelions without damaging the soil. When using this method, it is best to pull up dandelions before they begin to produce and release seed. As much of the dandelion's root as possible must be removed. Mowing of the heads of dandelions before they release seeds will not kill dandelions but can prevent them from spreading.

Herbicide Use in Turfgrass Control

A single, successful form of control for dandelions in turf grass has not yet been discovered. Diligent pulling of young dandelions can be helpful. Glyphosate herbicides can also be used to spot treat individual dandelion plants, but this method kills grass so the open spots need to be recovered with grass seed. Pre-emergent herbicides (applied before dandelion appears) are generally unsuccessful against dandelion with the exception of the broadleaf pre-emergent herbicide isoxaben. Pre-emergent herbicides must be applied to the ground prior to the appearance of dandelions. Post-emergent broadleaf herbicides can kill dandelions after they have germinated and appeared; 2, 4-D works well for dandelions that are thoroughly established. MCPA, mecoprop and triclopyr have been shown to weaken dandelions but will not kill them. When used properly, broadleaf herbicides are safe for grass.

Herbicide Use in Ornamental Beds

Prevention is the best option for control of dandelions in ornamental plantings. Pulling up dandelions and applying a glyphosate herbicide to individual plants is a good time and money-saver. Make sure glyphosate does not touch or drift toward desirable ornamentals. Oxyfluorfen and isoxaben herbicides applied to the soil prior to the appearance of dandelions have been shown to be effective, but both methods require a licensed, professional applicator. A better method may be to mulch the bed with a landscape fabric. These are black tarps or fabrics that are laid in the ornamental bed and covered with organic mulch to block dandelion growth. Applying 3-inch-deep wood chip mulches can also prevent the growth of dandelion seedlings.

Other Considerations

Before purchasing a herbicide, read the product's label to ensure that the product will work on dandelions. When using herbicides, follow the product's directions carefully. If dandelions still exist in fall, spray them again with the herbicide of choice to weaken them before winter sets in.

References

• University of California Agriculture and Natural Resources: Dandelions
• University of Illinois Extension: Dandelion Control

Resources

• Alternative Nature Online Herbal: Dandelion