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Control Horse or Mare’s Tail – Equisetum Arvense

Horse or Mares Tail

Horse Tail Plot

Horsetail on the Plot

Horsetail or Mares Tail, Equisetum Arvense is, in my opinion, garden public enemy number one. It looks like it belongs in Jurassic Park and, unchecked, spreads like wildfire. It produces spores, spreads from the roots and even small pieces of root will grow into plants

In spring, brown green shoots appear with small cones at the tips that produce spores. (Arghh – millions of ‘em) and it grows away from creeping thin brown roots that you can hardly see as they are soil coloured. Digging out these roots is not feasible – they go down into the soil for up to 1.5 metres – yes, 5 feet.

After the spore producing shoots the ‘leaves’ or tails appear. These will die off as autumn turns to winter and the roots sit there waiting for spring when they start the cycle again.

It’s critical to controlling horsetail to hoe off the initial stalks to prevent them distributing the spores.

Controlling Horsetail with Contact Herbicides

The leaves have a waxy coat, which makes the plant highly resistant to contact weedkillers like glyphosate which many people are concerned about using. However, I have recently found a weedkiller that is pretty effective against horsetail and marestail. Neudorff Superfast and Long Lasting Weedkiller.

It is made from pelargonic acid which is found naturally in pelargoniums and maleic acid hydrazide. Maleic acid hydrazide has been around since 1895 and is well researched and understood. Since 1952 it has been used as a growth regulator on potatoes and onions to prevent sprouting.

Crushing the leaves to break up the coating helps weedkiller to penetrate and become absorbed but in large areas it is not so easy to crush all the leaves . However, glyphosate weed killer will have an effect and eventually kill the plant. You will probably need 5 or more applications. Knock it back, it re-grows and you repeat. I don’t think you can clear this in less than one season with glyphosate if that.

Another method is to thicken a mix of strong glyphosate with wallpaper paste or starch and paint it directly onto the fronds.

Mr D M Finnegan suggests this:

Try mixing glyphosate with a good squeeze of cheap washing up liquid. It works well the wax coating being broken down by the washing up liquid. This needs to be only used on a cloudy day with little or no wind. I water this on to avoid spray drift. The mixture tends to be a bit foamy. I then use a flame gun on what is left.

Glyphosate used to be considered a very safe and environmentally friendly herbicide but recently a number or reports have been published that cast doubt on this and you may wish to look at alternatives.

Amcide Ammonium Sulphamate Herbicide Control of Horsetail

Amcide Weedkiller ( Ammonium Sulphamate) was fairly effective although it could 3 applications to win. However it is now delisted and not legal to use or recommend it (see below)

Kurtail Herbicide Control of Horsetail

Kurtail is effective against mares tail with the benefit of you being able to cultivate as soon as the roots have died (allow 2 to 3 weeks)

For best results treatment should be made to actively growing weeds between 1st March and 30th September. Kurtail works only when plants are actively growing. Kurtail will give effective control of horsetail through foliar (leaf) application. Best results are obtained by applying to approximately 20cm of heathy plant growth above ground.

Avoid Spreading Horsetail

I’d recommend NOT digging where there is horsetail until it is dead for sure. Otherwise it just starts springing up from the root cuttings. Drying or drowning the roots prior to composting is a must.

Organic Control of Mare’s Tail (Horsetail)

I’ve been contacted by Mr Charles Bailey who points out that Horsetail is correctly applied to the weed growing on land whereas Mare’s tail is correctly applied to the weed growing in water.

Horsetail Mares Tail (Equisetum arvense)

Horsetail Mares Tail (Equisetum arvense)
a) The stalk with spore body appears in spring
b) The leafy fronds appear later to feed the roots

He also puts forth an organic control method, which he says is effective.

Without resorting to chemicals you can control/eradicate horse tail by digging/forking through the soil when it is in the right condition: i.e. not too wet and sticky! Once you have removed as much as possible, any that shoots is easily dealt with. Before it reaches 3 ins/7cm high, hoe off an inch below the surface.

Eventually the food supply in the root is exhausted. Let it get bigger than stated and food begins to be stored in the roots again, and round and round you go ad infinitum. Never touch Horsetail with a mechanical cultivator. If you do you will understand why it has been around for 60 million years

It’s worth pointing out – and my thanks to Chris Donohue here – that horsetail is effectively one huge plant whose roots may be 100 metres in length and outside of the area accessible to cultivation.

He states: “My own assessment is that if you have Horsetail, you will never get rid of it but you can prevent it spreading to your neighbours if you treat assiduously either with glyphosate or in setting up a deep control section – many horsetail horizontal roots are no more than 1 or 2 spits deep”

Neudorff Superfast & Long Lasting Weedkiller

I’ve had reports praising how effective this is against horsetail or marestail. It is freely available to allotment holders and home gardeners. It is safe, children and pets are able to enter treated areas as soon as the spray has dried. Treated areas can be replanted after just 2 days.

Full information on how it works can be found on Neudorff’s web site.


Kurtail (previously Kibosh) which is glufosinate-ammonium will kill all grass and broadleaved weeds it contacts in approximately 7 days and provide effective control of annual and perennial weeds including thistles, couch grass and mare’s tail (or horse tail).

Glufosinate is a natural compound isolated from two species of Streptomyces fungi. It inhibits the activity of an enzyme, glutamine synthetase, which is necessary for the production of glutamine and for ammonia detoxification. The application of glufosinate leads to reduced glutamine and increased ammonia levels in the plant tissues. This causes photosynthesis to stop and the plant dies within a few days Developed primarily for use with genetically modified resistant crops.

Kurtail is degraded after contact with the soil and crops can be drilled or planted immediately after application except on sands or very light or immature peat soils. When using Kurtail on these soils allow 3 days to elapse before planting or drilling or before emergence of crops drilled prior to treatment

Kurtail is professional use only – although it seems to be freely available on Ebay!


Amcide is no longer available as a herbicide. However I have seen ammonium sulphamate for sale on Ebay as a compost accelerator (with dire warnings about not using it as a herbicide!) Just thought you’d like to know.

Amcide (Ammonium Sulphamate) was an effective weedkiller used for killing tree stumps and brushwood clearing. In effect it is crooked sulphate of ammonia (a chemical nitrogen fertiliser). The plant absorbs it, taking it to the roots and dying.

After 4 weeks or so, it reacts with the air to form sulphate of ammonia – adding a nitrogen boost to the soil. Re-planting is safe after 6 weeks. It may make the soil more acid – so check pH.

More Suggestions for controlling Mare’s Tail (Horsetail)

Mark Mattocks says:

A personal experience on a few occasions is the fact that they don’t like to be crushed or abraded thus removing the silica coating. My first awareness of this was some 20 years ago. Next door to me was an empty plot, heavily covered with mares tails. I spent a couple of days dragging lightweight branches etc through the mare’s to the bottom of the plot to burn. About a week or so when round there again, where I had dragged the shrubs/branches the Mares tails had died off. Recent experience, the last three weeks or so walking the dogs (St Bernard’s) so big dogs the younger dog adores rolling in them and has killed off a large area, just by rolling in them.

Bill Biggs has cleared his problem:

A few years ago a neighbouring farmer kindly dropped a few tracker bucket loads of farm manure over my fencing, which I thicky spread, and left to winter, over my garden areas found to have Horse or Mare’s Tail. Don’t know if it was the natural acid content within the cattle manure or just good luck, but Horse or Mare’s Tail hasn’t been seen since. Hopefully the garden will continue to stay free of Horse or Mare’s Tail.

Next job is to try and get rid of bind weed.

David Hawes writes:

I have an allotment in the south east which has Mares tail. I have tried all type of ways to remove it and have come across a way that keeps it down. The mixture is 2 Table Spoons of Bicarbonate of Soda, 200 grams of table salt, 200 ml of water approx, 200 grams of washing detergent. Shake well and spray on the Mare’s tail level until it turns browny black then it is dead .Will not contaminate land .


Controlling Weeds


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