Horsetails (Equisetum species)

Horsetails are primitive, non-flowering perennial plants once grown for ornamental purposes. They are highly invasive and can reduce crop yields. All except the common horsetail are toxic to livestock.

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How does this weed affect you?

Horsetails are primitive, non-flowering perennial plants that are highly invasive. Horsetail is the common name used to refer to 30 species in the Equisetum genus, 12 of which are considered weeds around the world. Common horsetail (Equisetum arvense) and scouring rush horsetail (Equisetum hyemale) are of most concern in Australia. In high densities they also reduce crop yields by producing inhibitory substances that depress the growth of neighbouring plants. All except the common horsetail are toxic to livestock.

Horsetails have been grown and sold as ornamental plants in Australia.

What does it look like?

Horsetails are non-woody herbaceous plants. Depending on the species, heights vary from 5 to 120 cm with scouring rush horsetail up to 120 cm and common horsetail up to 80 cm high.

Key identification features

• Two types of stems are produced: pale-brown, unbranched stems that produce fruiting cones and then die back to the ground; and green, branched, hollow stems that do not produce fruit. The stems of common horsetail usually die back to the rhizomes each year, but in other species the above ground growth may survive over winter. Stems break easily at the joints and feel hard and rough due to their silica content.
• Inconspicuous leaves grow in whorls of 6 to 18 on the main shoots, joined at their edges to form black-tipped sheaths of teeth around the stems.
• Fruiting cones 1-4 cm in length grow at the ends of the stems and produce pale-greenish to yellow spores.
• The root system consists of rhizomes which can extend horizontally for up to 100 m below the ground.

Where is it found?

Horsetails are native to the northern hemisphere including Europe, Northern America and Asia. Horsetails are now naturalised in New Zealand, Madagascar and parts of South America. Common horsetail is used for medicinal purposes as a silica supplement and the buds are eaten as a vegetable in Japan and Korea.

In NSW most plants have been found in the Greater Sydney region. Plants have also been found in the Central Tablelands, North Coast and North West regions.

Maps and records

• Recorded presence of Horsetails during property inspections (Map: Biosecurity Information System - Weeds, 2017-2024)
  These records are made by authorised officers during property inspections under the Biosecurity Act 2015. Officers record the presence of priority weeds in their council area and provide this to the NSW Department of Primary Industries. Records reflect the presence of the weed on the date of inspection.
  
  

How does it spread?

Plants nearly always spread by rhizomes that produce new stems (shoots) throughout the growing season from spring to autumn. Small parts of the rhizomes from mature plants can break off and grow into new plants. Horsetails also produce spores that require prolonged periods of moist conditions to germinate successfully. Most spores die from moisture stress. New infestations can result when garden waste containing rhizomes is dumped or when plants are sold illegally for ornamental or medicinal purposes.

What type of environment does it grow in?

Horsetails naturally occur in cold to temperate regions with temperatures ranging from 5°C to 20°C and rainfall between 1000 and 2000 mm. They are mostly found in wet areas such as the banks and edges of swamps, rivers and lakes. They tolerate low nutrient levels and grow on many soil types. Common horsetail will grow in most places were there is sufficient moisture below altitudes of 300 metres. It usually grows in damp conditions in open woodlands, pastures, stream banks, embankments, arable land and roadsides. In Australia it has become invasive in areas with rainfall of around 1400 mm.  Scouring rush horsetail also prefers moist environments and infestations have occurred in NSW in areas below altitudes of 620 metres with annual rainfalls of 1100 – 1500 mm.

Acknowledgements

Written by Charlie Mifsud; Edited and prepared by Elissa van Oosterhout; Technically reviewed by Birgitte Verbeek, Melissa Kahler, Andrew Petroeschevsky.

References

CRC Weed Management (2003) Horsetails - Equisetum species Weed Management Guide

More information

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Control

Your local council weeds officer will provide assistance and control advice if you think you have found this plant. Control can be difficult. Silica in the plants limits herbicide penetration into the stems, and the extensive rhizome system also limits herbicide effectiveness. Mechanical controls such as slashing, mowing and excavating are likely to leave rhizomes that will regrow. Digging plants out by hand is effective over small areas if care is taken to find and remove all rhizomes and plant material.

Herbicide options

See Using herbicides for more information.

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PERMIT 13917 Expires 31/03/2025
Dichlobenil 67.5 g/kg (Casoron G®)
Rate: 18 g /m2
Comments: For use by persons employed or contracted by local control authorities or NSW DPIE. Spread granules evenly over the soil of area to be treated and immediately water in after application. DO NOT apply to water which will be used for crop irrigation, livestock watering, or human consumption.
Withholding period: Not required when used as directed.
Herbicide group: 29 (previously group O), Inhibition of cellulose biosynthesis
Resistance risk: Moderate

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Biosecurity duty

The content provided here is for information purposes only and is taken from the Biosecurity Act 2015 and its subordinate legislation, and the Regional Strategic Weed Management Plans (published by each Local Land Services region in NSW). It describes the state and regional priorities for weeds in New South Wales, Australia.

Area	Duty
All of NSW	General Biosecurity Duty All pest plants are regulated with a general biosecurity duty to prevent, eliminate or minimise any biosecurity risk they may pose. Any person who deals with any plant, who knows (or ought to know) of any biosecurity risk, has a duty to ensure the risk is prevented, eliminated or minimised, so far as is reasonably practicable.
Central Tablelands	Regional Recommended Measure* (for Regional Priority - Prevention) Land managers should mitigate the risk of the plant being introduced to their land. Land managers should eradicate the plant from the land and keep the land free of the plant. A person should not deal with the plant, where dealings include but are not limited to buying, selling, growing, moving, carrying or releasing the plant. Notify local control authority if found.
Greater Sydney The Northern Beaches Council area is classified as the core infestation area. An exclusion zone is established for the rest of the region.	Regional Recommended Measure* (for Regional Priority - Containment) Whole of region: Land managers should mitigate the risk of the plant being introduced to their land. Within exclusion zone: Land managers should eradicate the plant from the land and keep the land free of the plant. A person should not deal with the plant, where dealings include but are not limited to buying, selling, growing, moving, carrying or releasing the plant. Notify local control authority if found. Within core infestation area: Land managers should mitigate spread of the plant from their land. A person should not buy, sell, move, carry or release the plant into the environment.
Hunter	Regional Recommended Measure* (for Regional Priority - Prevention) Land managers should mitigate the risk of the plant being introduced to their land. Land managers should eradicate the plant from the land and keep the land free of the plant. A person should not deal with the plant, where dealings include but are not limited to buying, selling, growing, moving, carrying or releasing the plant. Notify local control authority if found. This Regional Recommended Measure applies to Equisetum arvense
Murray	Regional Recommended Measure* (for Regional Priority - Prevention) Land managers should mitigate the risk of the plant being introduced to their land. Land managers should eradicate the plant from the land and keep the land free of the plant. A person should not deal with the plant, where dealings include but are not limited to buying, selling, growing, moving, carrying or releasing the plant. Notify local control authority if found.
North Coast	Regional Recommended Measure* (for Regional Priority - Prevention) Land managers should mitigate the risk of the plant being introduced to their land. Land managers should eradicate the plant from the land and keep the land free of the plant. A person should not deal with the plant, where dealings include but are not limited to buying, selling, growing, moving, carrying or releasing the plant. Notify local control authority if found.
North West	Regional Recommended Measure* (for Regional Priority - Prevention) Land managers should mitigate the risk of the plant being introduced to their land. Land managers should eradicate the plant from the land and keep the land free of the plant. A person should not deal with the plant, where dealings include but are not limited to buying, selling, growing, moving, carrying or releasing the plant. Notify local control authority if found.
Riverina	Regional Recommended Measure* (for Regional Priority - Prevention) Land managers should mitigate the risk of the plant being introduced to their land. Land managers should eradicate the plant from the land and keep the land free of the plant. A person should not deal with the plant, where dealings include but are not limited to buying, selling, growing, moving, carrying or releasing the plant. Notify local control authority if found. Your local biosecurity weeds officer can help to identify, advise on control, and how to remove this weed.
South East	Regional Recommended Measure* (for Regional Priority - Eradication) Land managers should mitigate the risk of the plant being introduced to their land. Land managers should eradicate the plant from the land and keep the land free of the plant. A person should not deal with the plant, where dealings include but are not limited to buying, selling, growing, moving, carrying or releasing the plant. Notify local control authority if found.
	*To see the Regional Strategic Weeds Management Plans containing demonstrated outcomes that fulfil the general biosecurity duty for this weed click here

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Reviewed 2023