How to Kill Horsetail Weeds Do’s and Don’ts – [6 Helpful Tips]

Horsetail is an extremely invasive and deep-rooted weed that can take over a lawn or garden seemingly overnight. To kill horsetail weeds down to the root, you will need to apply weed killers containing active ingredients like 2,4-D Amine, halosulfuron-methyl, or Triclopyr. These herbicides will kill weeds at the surface level as well.

Keep in mind that horsetail is an extremely tenacious plant, with root networks that extend several feet deep and can spread as far as 20 feet in diameter. As long as there is even a small portion of root in the soil, horsetail can resprout. Killing horsetail is a serious challenge, but it can be accomplished in a few ways.

How to kill horsetail weeds

Horsetail Weed Identification

Horsetail is a perennial which can be identified by upright shoots with round, needle-like “leaves” growing around the central stalk. It gets its name from its resemblance to a horse’s tail, but has also been compared to a bottle brush. Young horsetail resembles the end of a pine tree branch, although it is a more vibrant green than most pines.

Horsetail is a member of the fern family. Like its cousins, it prefers moist soil and can thrive in low-light, low-oxygen conditions. It typically grows well in acidic soils with high volumes of sand and/or clay.

The Do’s: 5 Ways on How to Remove Horsetail Weeds

Use the Right Chemical Weed-Killer

Roundup and other Glyphosate-based weed killers won’t work on horsetail. However, a top-rated horsetail weed killer has the ability to kill common horsetail both at the surface and down to the roots.

2,4-D Amine is a compound found in many weed-killing products available at local hardware and garden stores. Many are advertised with “2,4-D” prominently on the label. Lawn care professionals attest to the fact that if used properly, this is one of the few chemicals that can attack a horsetail root rhizome. Crossbow is a great weed control herbicide when dealing with horsetail.

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Halosulfuron-methyl is a compound found in sedge and nutgrass control products such as Sedgehammer. It has shown success in attacking horsetail root systems and killing the plant entirely. It may require multiple applications over a 6-12 week period to get results, but it’s a much better option than Roundup.

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Triclopryr uses the active ingredient, triethylamine salt, to move through plant tissue and prevent overall cell growth. Products like BioAdvanced Brush Killer with Triclopryr can be applied to control horsetail and kill the weed within 3 to 6 weeks.

Cut Horsetail Before Applying Weed Killer

Horsetail is notorious for its waxy, tough leaves. This waxy leaf cuticle serves as a natural barrier to toxins of all kinds. It also makes the plant incredibly resistant to many types of weed killers.

Before applying your weed killer of choice, cut the horsetail with a mower or garden shears. This will allow your herbicide to enter the horsetail’s system through the wound you’ve made. You will see faster and more effective results by cutting horsetail before applying weed killer.

You can skip this step if you plan to use Crossbow because it works best absorbing into the leaves of the weed.

Close up shot of a field of fully grown horsetail weeds

Improve Soil to Discourage Horsetail

Horsetail thrives in poorly drained areas with acidic soil (typically sandy or clay soils). The following processes will help change soil conditions to make them more suitable for desirable plants and less suitable for horsetail:

  • Improve Drainage: You can improve drainage by filling any boggy or low spots with additional soil. Dig drainage trenches to siphon runoff away from your lawn or garden. Perpetually moist areas are a haven for horsetail and typically a deathbed for the plants or grass you wish to grow.
  • Apply Dolomite Lime: Horsetail thrives in acidic environments. Lime works to reduce overall soil acidity and common horsetail won’t be able to grow as strong in less acidic conditions. By changing soil chemistry, you can also make your other plants healthier, thereby choking out horsetail. Just be sure to follow the directions on the packaging of the dolomite lime you purchase before application.
  • Fertilize: Two weeks after applying dolomite lawn, add fertilizer to your soil. If you apply lime and fertilizer at the same time, the lime and nitrogen will work against one another. Water the lime into the soil, wait at least 14 days, and then apply a slow-release, high-nitrogen fertilizer. The fertilizer won’t kill weeds, but it will boost desired plant growth and alter conditions against horsetail.

Use Casoron Pre-Emergent Weed Killer

The best way to stop horsetail in its tracks is to kill it before it has a chance to grow. In early spring, apply Casoron pre-emergent to kill horsetail weed seeds and prevent any horsetail plant growth.

Be sure to water after applying Casoron, or apply it right before any expected rainfall. Casoron needs to be soaked into the soil in order to create a barrier and prevent any field horsetail from sprouting.

It’s also important to be very careful when applying Casoron, as it is a non-selective herbicide. This means it will kill just about anything it touches. Do not apply Casoron if you have desirable plants nearby that you wish to keep.

Control Any Returning Spores

By using one or more of the previous methods, you should have seen some success with your horsetail weed control. With that being said, you should still remain vigilant during the growing season. Horsetail is a tough customer. Look out for greenish-brown shoots with a cone at the end. These are horsetail shoots. That cone contains spores that will spread more horsetails.

Keep any resurgent horsetail under control by spraying, cutting, or pulling these new shoots. With a little persistence in your horsetail weed removal efforts, your problem will be a thing of the past.

Horsetail weed stems pushing through the soil early in the growing process

The Don’ts: 6 Things to Avoid When Getting Rid of Horsetail Weeds

Horsetail is a unique weed due to its membership in the fern family and its large root system. Several weed-killing tactics won’t work when trying to get rid of horsetail.

Do not attempt the following horsetail removal methods. They will cost you both time and money without killing the plant.

Don’t Use Vinegar as a Natural Weed Killer

Vinegar can be used to control horsetail aboveground, but it won’t kill the weed down to the root. Applying a high-strength vinegar, mixed with a small amount of dish soap can kill the above-ground growth of horsetail quickly, but you will be left with underground rhizomes that will continue to grow into new undesirable weeds. The acetic acid in the vinegar only attacks horsetail leaves and stems, but not horsetail roots.

Even horticultural vinegar, which contains 15-20% acetic acid will be ineffective at killing horsetail. The acetic acid in vinegar will “burn” the aboveground portion of horsetail, which may cause you to think you’ve won. However, the acetic acid in vinegar is neutralized by soil. This means vinegar won’t penetrate and kill horsetail roots. The plant will simply sprout again.

Don’t Use Roundup

Roundup does not kill horsetail weeds. Not only do the waxy leaves of horsetail plants protect them from most topical herbicides, but the plant is also very resistant to Glyphosate, the active ingredient in Roundup. Glyphosate horsetail weed killers simply do not exist, so always go with something like Crossbow over Roundup.

Don’t Use WD-40

You should not attempt to eradicate horsetail with WD-40. Not only will WD-40 not penetrate and kill horsetail weed roots, but is also incredibly toxic to add to the soil. Even a little runoff from WD-40 can prevent future growth for surrounding plants for several years. There are plenty of environmentally safe alternatives to WD-40.

Don’t Use Bleach

Like vinegar, a spray bottle full of bleach mixture will not wipe out your horsetail infestation. Bleach is a base that burns plants due to its high pH. However, it won’t kill horsetail to the root, so the offending weed will grow back. The reason herbicides work so much better than household products is because they’re made with chemicals that infiltrate plants and disrupt cell division, causing complete plant death. Bleach simply doesn’t have the same weed-killing power.

Don’t Use Sheet Mulching or Ground Covering

Horsetail thrives in the low-oxygen, low-light environment created by covering an area with plastic sheeting or thick mulch. Not only that, but because horsetail establishes such large root networks, it will find uncovered places to sprout. You may hold it back for a season with this method, but sooner or later, horsetail will push up through your mulch, around the edges of it, or even begin to grow underneath your ground covering.

Don’t Hand Pull Horsetail Weeds

Don’t expect to get rid of horsetail by hand. Horsetail roots can grow to depths of five feet. You won’t kill the plant simply by pulling the exposed portion. If you follow this method you can expect to battle resurgent horsetail year after year.

How to Get Rid of Horsetail Weeds

Horsetail is resistant to Roundup, can survive with very little light or oxygen, and has deep roots, so it’s extremely hard to kill. By using a 2,4-D herbicide, or a sedge and nutgrass product such as Sedgehammer, you can eliminate horsetail completely. With proper drainage, soil management, and fertilization practices you can make your lawn and garden resistant to horsetail.

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