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.
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
- Brush B Gon
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 killed horsetail in your yard?