How to Kill Horsetail/ Marestail?
What is horsetail and mare's tail?
Horsetail also known as Mare’s tail and nicknamed the bottle brush plant (Equisetum arvense) is extremely hard to control due to its deep rooted nature and thick silica structure. We are often asked what will kill the horse tail weed?
There are a number of methods that can be used to control mare’s tail, with varying degrees of success. It’s extensive root system means that herbicides give the best levels of control. For several years Kurtail Gold was the gold standard in the marestail control sector. This product was withdrawn in January 2019 leaving a gaping hole in the market. ProGreen have now launched the next generation of herbicide for marestail control - Kurtail Evo.
Another way of control is to use cultural methods on the horsetail plant, such as cutting back and liming; however these non-chemical methods often only reduce the mare’s tail infestation – not kill it.
Gardeners need to be careful with a weed like horsetail as not only does it spread via spores but it only takes a finger sized piece of root horsetail to regrow. It should be remembered that killing mare’s tail, horse tail is not a quick fix and regular re-applications of herbicides and repeated ongoing cultural control may be needed.
STEP BY STEP GUIDE TO CONTROLLING HORSETAIL / MARESTAIL
CHEMICAL CONTROL METHOD
1. Remove dead marestail stems/stalks ideally in the winter months or alternatively early spring
2. Do not spray too early but wait until the horsetail is approximately 15 cm – 20 cm high (approx. 4 - 6 inches high) and looks like a small bottle brush
3. Spray using a herbicide such as Kurtail Evo onto to the weed. Spray on until the plant is fully covered with a fine or medium spray.
NB: Do not worry if the marestail is taller than 15 – 20 cm high, it can still be treated using a herbicide, but the level of control may not be as effective
4. The horsetail, marestail will usually take 1 – 2 weeks to turn brown, however it will take longer to disappear and be killed. The longer you can wait the better results you will get
Progreen Tip – You can check if the plant is dead by breaking off a small piece of the stem near to the ground. If it is still green in the centre the plant has not yet fully died back
5. When the marestail is black and dead it can be raked and cleared away – ideally burnt or put in a garden recycling bin. It is recommended that horse tail is not composted – due to its ability to regrow from very tiny root particles
6. Often annual repeat applications are needed. In some instance Marestail / Horsetail will never totally disappear but this method will certainly reduce your levels of infestation and is considered the best method of control and killing marestail
To get good control of marestail you need to be consistent and persistent.
NATURAL CONTROL METHODS
LIMING TO CONTROL MARE’S TAIL / HORSETAIL
1. Some schools of thought are that horsetail can be controlled by raising the soil pH. This can be done by liming the soil to raise the pH levels. Increasing soil alkalinity can discourage the horsetail plant, as can improving soil drainage in the vicinity.
2. It is recommended to use a product such as Calcium Lime. Application rates vary dependent on soil types
a. Typical rates 900 g per 9.5 square metres (2 lbs per 100 sq ft)
b. Sandy or slightly acidic soils rates 450 g for 1.85 – 2.8 square metres (1 lb per 20 – 30 sq ft)
c. Clay soils – 900 g per 2.8 square metres (2 lbs per 20 sq ft)
3. Wait a minimum of 2 weeks and then apply an appropriate fertiliser for the desired plants in which the mares tail is growing. Do not apply the lime and fertiliser at same time as this will reduce the effectiveness of the liming. It is recommended to use a synthetic fertiliser or manure to a 2 inch depth
4. This method should be carried out every one to two years. Control may not be complete with this method, but reductions will be seen. Full control of mare’s tail using the liming method can take up to five years to see results. It is worth noting that little scientific information exists on the success rate of this process, but anecdotally people have seen results from using this method to control mare’s tail.
OTHER NON-CHEMICAL ORGANIC CONTROL METHODS FOR MARES TAIL / HORSETAIL
Horsetail can be removed by hand but is a very difficult task and a massive amount of patience is needed due to the heavy root system.
1. Shoots should be removed as soon as they appear, as this can reduce the level of infestation. This must be kept on top of with regular removal. This method will take a number of years and is not guaranteed.
NB: If you want to control the horsetail plant with a mare’s tail weedkiller then do not remove any shoots. The plant needs to be actively growing and healthy to get the best control levels.
2. It is generally not advised to try to dig out mares tail as it is known that a small piece of root can easily grow. Do not rotovate ground where horsetail is growing as this will make your problem worse
3. Horsetail that appears in a lawn can be kept under control by regularly mowing, however this method will not get rid of this problem weed.