Gardening Plant Problems Weeds

What Kills Weeds Permanently?

Dandelion bloom closeup.
David Beaulieu

Some gardeners are more tolerant of weeds than others. Certain weeds have admirable qualities; for example, a little creeping Charlie (Glechoma hederacea) rewards you with attractive flowers and a wonderful aroma when you mow. If you prefer to rid your garden or lawn of unwanted plants read on and learn what kills weeds permanently.

Is It Possible to Kill Weeds Permanently?

Gardening teaches us that permanence in the landscape is likely impermanent, especially regarding weeds; no yard is likely to be forever weed-free.

To live weed-free you have to decide if you're willing to pay the price to kill these nuisance plants. Are you prepared to keep up the necessary maintenance for a pristine yard? Or can you live with the effects of herbicides that effectively kill weeds?

What Is a Herbicide?

Herbicides are chemicals or natural products (like salt or vinegar) used on lawns and gardens to control and kill weeds and other unwanted plants.

How to Control Grass and Weeds in Driveway

Methods for Killing Weeds Permanently

Both chemical and natural methods for killing weeds are available. In addition to simple hand-pulling, consider two other natural ways to kill weeds:

Soil Solarization

Soil solarization kills weeds before they emerge by attacking them at the seed stage of the cycle. This method works best if you do it in June or July when there are long sunny periods. Here are the basic steps:

  • Prepare by raking the area thoroughly so that nothing sharp is protruding.
  • Moisten the soil.
  • Lay down a clear polyethylene sheet and secure it with stakes or rocks on the edges.
  • Keep the sheet of plastic in place for two months. The intense heat cooks the weed seeds before they sprout.

Vinegar

Vinegar is a natural herbicide for annual weeds. Strong horticultural vinegar works best because vinegar from the grocery store is not strong enough to kill weeds. When applying horticultural vinegar, be mindful of nearby plants so you don't accidently overspray and kill a desired plant.

Learn when annual weeds set seed and target them before they produce a new generation. Spray the vinegar during a sunny period because you don't want rain to wash away vinegar before it takes effect. Plant death will result when the harsh sun hits the leaves of the weeds treated with vinegar.

Injecting Herbicides

There are also non-natural methods using chemicals applied in different ways. You could use an injection tool that discharges herbicide directly into the thick stems of large, tough perennial weeds, such as Japanese knotweed (Polygonum cuspidatum).

Though this method is uncommon, it can work well to control non-selective herbicides because you don't have to worry about getting the harmful chemicals on the surrounding plants you wish to keep.

Spraying Herbicides or Applying Granules and Liquids

Herbicides are usually sprayed or come in liquid or granular form. For example, in the spring you might use a pre-emergent liquid or granular herbicide to kill crabgrass (Digitaria spp.) seed. For existing weeds, spraying the foliage to kill plants is effective but avoid spraying on windy days.

Preventing Weeds Before They Happen

Using landscape fabric and mulch together is the best method for weed prevention.

Landscape fabric is rolled out across the ground to act as a barrier against weeds where they usually grow. Mulch is applied on top of the fabric to protect it from harsh UV rays, Often, mulch is used by itself for weed suppression.

Drawbacks of Weed Control

Every weed control method has drawbacks, from health risks to environmental harm, including a chemical herbicide's negative impact on pollinator populations. Even natural weed-killing methods, like salting, require sufficient quantities to kill weeds but can also damage the soil by reducing the amount of water for plant roots to draw on for nourishment.

If you share these concerns, consider using soil solarization and other preventive ways to control and kill weeds.

The Spruce uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Herbicide Options for Managing Common Lawn Weeds in Maryland | University of Maryland Extension.

  2. Basics of Salinity and Sodicity Effects on Soil Physical Properties. Montana State University.