Horsetail has two distinct types of growth. The first type appears in early to mid-spring; these early shoots are curious-looking, light tawny brown, about 30cm tall, and easily mistaken for toadstools. Like other early plants (ferns, mosses, liverworts), horsetail reproduces by spores, and it is these early shoots that have spore-bearing cones (strobili) at their tips.  

The second type of growth appears in late spring and grows throughout the summer. These shoots are green, reaching about 60cm in height, and en masse resemble a miniature conifer forest. The stems grow in segments, producing dense whorls of needle-like branches. They die back in autumn, leaving a system of dark

Rhizomes are creeping swollen root-like structures that are actually adapted stems. Roots, stems with leaves and flowers are produced along its length. See plants such as Anemone nemorosa, bamboo, canna, border iris.

Tubers are swollen, usually underground, parts of a stem or root used to store food by the plant. They have buds that can produce new plants. Examples are tuberous begonia, cyclamen, dahlia and potato.

tubers

Although often viewed as a weed, horsetail does have an unusual beauty and is of interest as a ‘living fossil’, belonging to a group of plants that predate dinosaurs. Since ancient times people have used horsetail in herbal remedies to treat a range of ailments. It is also used to make an organic liquid fertiliser, with some claims that it has antifungal properties.

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Horsetail is a food plant for the rosy rustic moth 

Here are our answers to your most common questions about dealing with horsetail:   

How invasive is horsetail? 

Horsetail is a very successful plant, able to spread by spores and rhizomes. The early shoots in spring produce spores that are dispersed long distances by the wind, but the spores are short-lived and need damp conditions to germinate and grow. Horsetail is more likely to spread by rhizomes, as these can grow in a range of conditions. 

Its rhizomes spread slowly but can be up to 2m (6½ft) deep, making them difficult to remove, especially when intertwined with roots of other plants. They can easily cross boundaries, so horsetail may enter gardens by spreading underground from neighbouring properties. Small sections of rhizome can also regenerate, meaning horsetail is often spread unintentionally by chopping up rhizomes when digging or rotavating, or by moving plants, compost and soil containing pieces of rhizome.

Do I need to get rid of horsetail?   

No – it isn’t necessary to get rid of horsetail. When growing among trees, shrubs, or vigorous herbaceous perennials, horsetail won’t cause any significant competition and its presence in parts of the garden increases biodiversity and provides shelter and food for several invertebrates.  

Many gardens contain horsetail, and it doesn’t necessarily make a garden less attractive or an allotment less productive, so long as its spread is managed. For example, some areas of RHS Garden Wisley contain horsetail. Here it is managed by hand pulling all the green stems in June, with a second weeding session in late summer to remove regrowth. This approach controls the horsetail enough for other plants to grow and produce an impressive display of flowers.  

However, as its green stems can form dense ground cover from late spring to autumn, it is a good idea to control the growth of horsetail in parts of your garden where it might smother and outcompete seedlings, or smaller and less vigorous plants.

Epimediums growing untroubled by horsetail 

Many crops, including potatoes, grow well despite the presence of horsetail 

What is the easiest way to kill horsetail?  

If you have horsetail growing where it is not wanted, there are several ways to control it:   

• Pull or cut off new growth – remove shoots as soon as they appear above the ground to weaken horsetail. This will keep areas of soil clear, giving seedlings and other small plants a chance to establish.      
• Fork out rhizomes – use a hand fork or border fork to remove rhizomes; doing this regularly will weaken growth and, if done over several years, can potentially eradicate horsetail. If growth is from small sections of rhizomes that have recently been introduced to your garden, then careful removal of rhizomes and close monitoring for regrowth can eliminate horsetail before it gets established.  
• Smother plants – cover with a layer of compostable material, such as cardboard, and then a layer about 20cm (8in) thick of organic matter, such as bark or wood chips. Alternatively, use a heavy grade biodegradable mulch matting. This will block light and reduce growth, eventually causing the root system to die. Keep soil covered for several years, topping up the mulch layer when necessary. 
• Shade out plants – plant densely with evergreen shrubs to weaken horsetail growing beneath. Horsetail thrives in open sunny positions and will lose vigour in shady conditions.   
• Mow regularly – if horsetail appears in a lawn, mow regularly to weaken and eventually eliminate it. Laying turf over an area containing lots of horsetail and mowing it regularly is an alternative to covering the ground, and has the benefit of giving you an area of usable space during the process.     
• Avoid disturbing the soil – horsetail can regenerate from tiny fragments of rhizomes, so avoid digging or rotavating the soil where it grows.  

Forking out horsetail is an effective control method 

Should I use weedkiller? 

No, as non-chemical control methods are effective, even if time-consuming, there is no need to use weedkillers. For more information, see our page on Weeds: non-chemical controls.     

Using a systemic weedkiller (sometimes recommended for horsetail control) is not a quick or easy option. Due to horsetail’s scaly, moisture-resistant leaves and its deep network of roots/rhizomes, weedkillers available to home gardeners are often ineffective and may take numerous applications over several years to have any significant effect.  

The RHS does not support the use of weedkillers and recommends that alternative control methods are used. However, we do note that when gardeners struggle to control plants with cultural methods, regulated weedkillers/pesticides for home gardeners are available for use legally. Garden centres and large retailers selling weedkillers have trained staff who can advise on suitable products for your needs.