killing weeds on edges

Asked March 5, 2020, 8:12 PM EST

What is a good product to use to kill weeds on driveway borders? We have over 1/4 mile of rotomill driveway bordered by pasture, housing, barns. The area to spray has annual and perennial broadleafs and perennial grass. We would like to use the least destructive spray possible but realize that given our goal of eradicating multiple types of weeds will require some power. We also understand it will require repeated sprayings as weeds will reseed and/or increase by root growth.

Ottawa County Michigan

3 Responses

Likely your best product would be one containing the active ingredient glyphosate. Example products include Roundup Super Concentrate and GroundWork Super Weed and Grass Killer, though there are many others. Be sure that the product you choose only contains glyphosate. Pelargonic acid and diquat are also ok additions, but other active ingredients, such as imazapyr and imazapic can move through the soil profile and cause damage to trees and other woody species. If there are no trees in the areas you'll be spraying, let me know and we can discuss these longer lasting products further.

When using products containing glyphosate there are a few important points to consider. First, as with any pesticide, remember to read and follow all labeled instructions. Second, glyphosate is a broad-spectrum herbicide, meaning it will injure or kill other plants contacted during application, so care is needed to avoid green plant material, exposed roots, and injured bark of desired plants. Third, glyphosate is relatively safe in the environment when used as labeled. It adsorbs strongly to soil in most cases (i.e. clay and organic matter), allowing even sensitive crops to be planted shortly after application; meaning no carry over issues are expected. Finally, glyphosate alone can take up to 14 days to show full activity under ideal growing conditions. Retreatment of the area may be needed depending on the degree of infestation. Glyphosate is most effective for perennial weed control in the fall but can be applied anytime the plants are actively growing (temperatures consistently above 50F).

Thank you very much for this excellent information.

There those who feel a vinegar and salt spray is effective. There are many recipes on the internet. Can you provide any data on effectiveness and more importantly effect on soil and nearby plants?

There are a lot of "home remedies" on the internet, so I am glad you asked.

Vinegar and salt will injury or kill plant tissue that is contacted. They are non-selective or broadspectrum (i.e. affecting all plants) similar to glyphosate. There are a couple issues with the home remedy approach though that may make it undesirable. First, vinegar and/or salt will only kill the material contacted, so for the perennials you are dealing with it may suppress but not kill the plants due to their extensive root system (glyphosate is a systemic herbicide, so it will move within the plant into the above and below ground tissues resulting in a more complete kill). Second, both vinegar and salt can alter the soil environment. The first can lower soil pH and the second can increase soil salinity. If you plan to grow any other types of plants in this area altering the soil in these ways is likely not desirable. These products can also have negative impacts on concrete if you have any sidewalks or other concrete in the area.

All this being said, we do occasionally use salt to suppress weeds in the cracks of our it does have it's place under certain circumstances.

Please let me know if you have more questions.