How to tackle knotweed shoots on your construction site
Left untreated, knotweed can cause major structural damage. An infestation has such severe consequences that developers are obliged by law to deal with it swiftly and efficiently.
Knotweed can penetrate tarmac and paving, and undermine foundations. If left untreated the thickets attract vermin and trap litter. Large growths can disrupt sight lines on roads and railways and damage flood defence structures.
Topsoil movement and construction traffic are the main ways in which knotweed spreads.
As the consequences are so far reaching, local councils and the police have the power to issue notices under the Anti-Social Behaviour, Crime and Policing Act 2014 to ensure it’s properly dealt with.
1. Request a site survey
Developers should thoroughly survey the site before making the decision to purchase. Its presence may stop your project entirely so you’ll need to take it into account when assessing the profitability and the timescale of the venture.
You definitely should consider including the cost of knotweed management in the purchase agreement. In case of contamination, you must have a plan of action and staff to oversee the process.
2. Isolate the infestation
Generally the contamination extends around 7 metres horizontally from the nearest growth. As knotweed propagates through deeply penetrating, underground rhizomes, test pits should be dug to determine the precise extent of the problem. The area must then be fenced off and warning signs posted.
Use of tracked machinery must be limited until the knotweed has been cleared. Otherwise vehicles are in danger of spreading contaminated soil to other locations.
Seek professional knotweed removal services from a company with experience handling large construction projects.
3. How to tackle knotweed shoots on your construction site
Don’t be tempted to simply spray with herbicide. This may appear to be the cheapest option as it works fairly quickly by destroying the visible shoots. However this is only a short-term measure and certainly not a solution, as it does nothing to kill the underground rhizome network.
The most effective method is to carefully dig out all the leaves and stems above ground and the soil down to at least 3 metres in depth.
As knotweed can lie dormant for years the site shouldn’t be disturbed. Future owners must be notified of its presence.
The infected areas should still be treated with herbicide as knotweed is remarkably persistent and re-growth is likely, even when all procedures have been correctly followed. The best way to deal with Japanese knotweed is to hire removal experts that can eliminate the problem and stop it from re-growing in the future.
4. Dispose of the waste safely and legally
If on-site disposable isn’t possible it needs to be removed to a licensed landfill site, accompanied by Waste Transfer documentation.
Don’t forget that the contaminated material is classified as ‘controlled waste’ and you have a duty of care to dispose of it correctly. Until this happens, you’re liable for all parts of the process.
Burial shouldn’t take place near a water course to prevent the risk of further contamination.
Again, your professional removal service will dispose of your waste legally and responsibly, saving you hassle and potentially large legal fines.
If you’re still unsure how to tackle knotweed shoots on your construction site, the safest and most effective way to avoid the hazards posed by this pernicious plant is to consult the experts. This will solve the problem and ensure you meet your legal obligations.