I was told by the landscape professional who designed my yard that planting giant horsetail behind an expensive chemical barrier (BioBarrier) would prevent it from spreading in my garden. No problem.

This statement could not be further from the truth.

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Giant Horsetail Is an Invasive Weed

Giant horsetail is horrible. Stay miles away from it. In fact, I would stay away from all varieties of horsetail. Horsetail grows in the wild but it’s also sold at almost every nursery. Avoid it at all costs, especially the giant kind which was recommended for our yard.

Don’t let people tell you that horsetail in a container will be okay. All it takes is for one stalk to break off and blow away without you noticing. That stalk can root in your yard and take over. It can spread underneath your driveway to the other side, and go deep under concrete fence footings to reach your neighbor’s house. I found it traveling under concrete at distances of up to 20 feet.

This will create a huge problem for you and potentially your neighbors. I would estimate that a handful of plants has cost thousands of dollars in trouble.

Weed Killers We’ve Tried

We tried a long list of chemicals. I hate applying anything that isn’t organic to our yard but we were left without a choice. These did not work:

  • Anything natural
  • RoundUp
  • Brush B Gon
  • Remuda

We also tried digging it up as well as suffocating it with a barrier. These tests remedies were performed over the course of a few years so rest assured that we did our due diligence.

How to Kill Horsetail

The local nursery who planted this invasive weed in our yard was also frantically trying to find a remedy. Finally, they started using a chemical called SedgeHammer to try to prevent the horsetail’s rapid spread and eventually kill it off.

A nursery staffer started coming by once a week to apply SedgeHammer as it lists Equisetum Arvense (horsetail) as something it can kill. Over the course of a month, I noticed growth slow down.

It’s completely unnerving because, supposedly, the SedgeHammer kills the horsetail stalk from underneath the dirt so the top stays green, and even grows a little bit.

The stalks will eventually shrivel up and die. Thicker giant horsetail stalks take longer to die. The new, skinny ones will totally die off with one application. 

It was hard for me to measure the progress really since I swore that I would not go digging around to check if the roots were dead.

The nursery marked treated stalks with orange paint so that they could measure progress. I shut off the irrigation in the area where it was growing.

Our remedy took much longer than the two weeks the SedgeHammer website implies the product can control problems in.

In fact, it took months of regular applications. The following spring, I noticed new growth that we had to apply more SedgeHammer to.

A year later I spotted more new growth that was treated. To this day, every so often we’ll spot a sprig of giant horsetail but it’s nothing compared to what the problem used to be.

So, if you have horsetail, you may want to try SedgeHammer but be diligent about applying it frequently. Please do your research before you apply anything like this yourself to decide if it’s right for you because it is poison. It’s the only product that killed giant horsetail in our yard.

But do yourself a favor and avoid any kind of horsetail.

How have you gotten rid of horsetail in your yard?

Katie Dillon is the managing editor of La Jolla Mom. She helps readers plan San Diego vacations through her hotel expertise (that stems from living in a Four Seasons hotel) and local connections. Readers have access to exclusive discounts on theme park tickets (like Disneyland and San Diego Zoo) and perks at luxury hotels worldwide through her. She also shares insider tips for visiting major cities worldwide, like Hong Kong, London, Paris, and Shanghai, that her family has either lived in or visits regularly (or both).

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  1. Pingback: Tweets that mention Killing Giant Horsetail Update #2 -- Topsy.com
  2. I fighting vineweed here. The roots of vineweed can go as deep as 20 to 30 feet. It will choak everything else off. It’s a constant battle. You have to keep any vegetation that comes up from it pulled. Don’t let the leaves get that sunlight or the roots just keep on growing. It spreads really fast.
    Another awful plant I see in stores/catalogues alot is seddum. Man that stuff takes over and blows everywhere and reroots itself.
    My mom got it in her yard from the neighbors stuff blowing over. It took about four years to finally get rid of it. It’s suppose to be a ground cover, but it just takes over. Nasty!

  3. Sorry, about post above, I meant to say I’m fighting vineweed here. Having problems with my glasses, need a newer prescription of glasses I think.

  4. Oh my goodness! I feel so sorry for you trying to deal with this! Good tips! I have seen inpenatrable fences of this horrible scorge…I
    check out my link above for an article I wrote on the evils of this plant…which might actually be an alien from another planet-lol!
    .-= Cool Garden Things´s last blog ..How to Grow Avocado =-.

  5. Not sure if last post went through-I just thought you would enjoy this link about Horsetail that GartenGrl wrote for our blog Cool Garden Things -Weed Watch
    .-= Cool Garden Things´s last blog ..How to Grow Avocado =-.

  6. I am having the same trouble here at the North Carolina Coast. — Any updates on your experience with SledgeHammer ?? I have located two dealers here in town and WILL give it a determined try. Thanks.

  7. Horsetail is a great herb. It is high in silica, which helps build strong bones, nail, hair. Look it up on the web. It’s an awesome herb. I have some planted in my backyard and it does not escape. Of course, I live in Arizona, where things don’t live if they are not watered manually.

    but horsetail is a GREAT herb. I BUY it, however it has to be organically grown. You could possibly start your own herb business or sell it to herb businesses that use large amts of it. IF it’s not sprayed or hasn’t been in 3 yrs. Which it doesn’t look like yours is organic.

    If you have something invasive and you haven’t been able to get rid of it, take a clue from those in the SE USA. They have found ways to USE kudzu!

    God speed.


  8. I have a large area of horsetail planted in my yard. Before I apply Sedgehammer, is there a benefit to cutting it down to ground level and then applying the herbicide?

  9. Pingback: Plants I Should Not Have Planted In My Yard | San Diego Landscaping
  10. We’ve had horsetail growing out of control in our yard since we moved in over 8 years ago…We made the mistake of cutting it down once and it proliferated. We are finally ready to tackle this beast…I would love to hear how this treatment worked for you. Were you ever able to plant food?


    1. Luckily, the horsetail lives in places where we had no intention of planting food. It has worked. However, I just noticed a few new shoots pop up. It’s been about two years since our last SedgeHammer application though so I’m pretty happy with that, compared to where we started. I have replanted the area with other plants.

  11. and you have not even met this one!!!!: Some Equisetopsida were large trees reaching to 30 meters tall!!!

    “An Introduction to the Genus Equisetum and the Class Sphenopsida as a whole”. Florida International University. Retrieved 2009-07-22.