Horsetail & Mare's Tail FAQs

Here are some of your top frequently asked questions, on the weed horsetail, answered.

Horsetail is an easily recognised weed which in its early stage of growth looks like small asparagus spears which then develop fir tree like fronds which appears throughout summer. It can reach between 20-60cm tall and can spread rapidly through its creeping rhizomes and spores.

Horsetail and mare’s tail is the same weed. The name "horsetail" is derived from the Latin Equisetum which translates as equus, meaning horse and seta which means bristle or hair. Its full name is Equisetum arvense which translates to Field Horsetail.

Use of herbicides such as the total weed killer Kurtail Evo or the selective weed killers Kurtail Lawn or SBK Brushwood Killer have been found to be most effective for mare’s tail.

For more information on how these work, please see our How to kill mare’s tail and horsetail blog.

The most effective way to control mare’s tail is to treat it while it is actively growing, typically when plants are around 20–60cm tall, using a suitable herbicide such as Kurtail Evo (total weed killer), Kurtail Lawn (grass safe) or SBK Brushwood Killer (grass safe). For this reason, cutting off the spore heads is not recommended. However, products such as Amvista Spore Stop can be used as a physical barrier and sticker to help prevent spores from being spread by the wind.

Mare’s tail is a poisonous weed if it is consumed raw due to the heavy content of silica. Grazing animals would usually avoid eating horsetail however as it dies back it does become more palatable. For this reason it is important to keep grazing animals away whilst the plant dies off when it has been treated with weed killer.

If the horsetail was growing in your lawn, mowing the grass will keep the plant down and stop it from gaining height at that moment. However, due to their extensive root systems, it will not stop the weed from spreading. The only way to stop the weed from spreading is to kill it using either SBK Brushwood Killer, Kurtail Lawn or Kurtail Evo. For more information on this, check out our How to Remove Horsetail Weeds Step-By-Step Guide.

In order to kill the mare's tail plant in a lawn, you would need to use the selective weed killer options, either Kurtail Lawn or SBK Brushwood Killer as this kills the weed but not the surrounding grass. To find out more about the horsetail/mare's tail weed, take a look at our How to control horsetail (mare's tail) guide.