Darren Greatbatch, Specialist Advisory Manager, Amenity & Invasive Weeds, at Environment Controls.
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Growing prevalence of Horsetail infestations
Whilst Japanese knotweed continues to present challenges for housing UK developers a new invasive plant is emerging as a serious threat. In this article we look at the problems it causes for UK house builders, and the perils of ignoring it!
Field horsetail (Equisetum arvense) as shown in the image is becoming an increasingly common problem on development sites across the UK. Its aggressive growth and resilience make it a significant concern for developers. Left unmanaged, Horsetail can quickly spread and establish dense colonies and creating persistent problems for construction projects.
Failing to identify and manage invasive plants like Horsetail before construction can lead to several complications:
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Structural damage: Building over Horsetail contaminated ground can result in Horsetail plants growing back through cracks in hard surfaces (including roads, pathways, patios) and other porous hard standing causing extensive damage.
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Extra costs: Re-using site soils contaminated with Horsetail can add considerable cost to treat the recurrence in private gardens and to compensate the end clients for the inconvenience.
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Delays: Discovery of invasive plants during or after the start of works can halt construction, require costly remediation, and impact project timelines.
- Reduced land value and saleability: The presence of invasive plants can deter buyers, complicate lending, and reduce the value of completed properties.
Early detection and establishing a management plan is essential:
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Early detection: Identifying invasive species before works commence allows for effective planning and treatment. If it is identified later down the line there are still remedial work options to resolve the issues.
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Accurate budgeting: Knowing the extent of infestation enables developers to allocate sufficient resources for remediation, avoiding unexpected costs later.
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Risk mitigation: Early intervention reduces the risk of project delays and legal complications.
CASE STUDY: BLOOR HOMES
Bloor Homes experienced the impact of Horsetail on a site planned for development. The site, a previous army barracks had several areas of Horsetail that had to be removed before works could commence, and having a professional survey of the land carried out at the right time minimised disruption.
Horsetail can plague newly completed development sites if major infestations are not controlled or removed prior to development. Regrowth in completed soft landscape areas can add major maintenance costs and regrowth through macadam can incur extensive repair costs. It is vital that major infestations are removed as part of site preparation works.
Environment Controls was contracted by Bloor Homes to survey the infested ground and remove all contaminated soils and plant material via excavation. As the site was planned for housing, excavation was the best option as with any rhizomatous plant any fragments of root left behind would generate new plants, leading to issues further down the line, during the build or dales phases.
With the Horsetail removed from site development could commence.
Challenges of Horsetail Removal
Horsetail is notoriously difficult to eradicate due to its:
- Deep and extensive rhizome network: Fragments left in the soil can regenerate, making physical removal challenging.
- Resistance to many herbicides: Standard treatments are often ineffective, requiring specialist knowledge and persistent management.
- Rapid regrowth: Even after initial clearance, Horsetail can reappear if the site is not properly monitored and managed.
Key Takeaways
- Pre-planning surveys are critical for identifying and managing invasive plants like Horsetail before construction begins.
- Ignoring horsetail can lead to significant project risks, delays, and financial losses.
- Specialist intervention is often required for effective Horsetail removal and long-term site protection.
Addressing these issues early ensures a smoother development process and protects the long-term value of your investment.
If you’d like one of our professional surveyors to visit your site, as part of a pre-planning inspection please contact the team.