Plan the perfect garden with our interactive tool →

How to Kill Johnson Grass With a Rope Wick Applicator

Johnson grass proves a troublesome and difficult invader once its tall, coarse blades find home in an area. Johnson grass appears near forest edges, riverbanks, and fields and quickly moves to suffocate eradicate nearby flora. The key to combating a Johnson grass infestation is to try and identify the problem early, then move swiftly to remove the grass. Small, individual clumps can be removed by hand, but larger patches realistically require chemical controls. Property owners should use a rope wick applicator to apply herbicide to Johnson grass if other desired plants are in close proximity.

Don a pair of protective gloves and mix a batch of glyphosate-based herbicide in the reservoir of the wick herbicide applicator. Consult the herbicide's label for the brand-specific correct mixture for wick applications.

Paint the blades of the Johnson grass with the wick, making sure that the grass is coated, but not to the point of dripping. Press the button on the applicator to release more herbicide into the wick. Continue until all Johnson grass clumps are covered with herbicide.

Wait two weeks. Dig up any dead clumps of Johnson grass with a hand spade, completely removing the rhizomes and root ball. Dispose of the dead Johnson grass in a trash bag.

Reapply the herbicide to any surviving Johnson grass clumps. Watch the affected area closely over the next few months, applying herbicide to any new growth as necessary.


New growth clumps can be removed manually to avoid the hassle on mixing and applying herbicide for one small grass cluster.

The Missouri Department of Conservation recommends applying glyphosate to Johnson grass when the plants are at least 18 inches tall and have yet to flower.

Constant mowing and late-season tilling prevents seed production and species propagation.


Avoid touching any plants you want to keep with the herbicide-soaked wick.

Do not overly saturate the wick, which could cause it to drip.

Garden Guides