Autumn is Here- Japanese Knotweed is Receding

Autumn: Knotweed is Dying Off (above ground…)

A long summer has drawn to a close and the temperatures have dropped. We noticed frost in Edinburgh yesterday morning so that spells the end for Japanese knotweed growth in Scotland’s capital as the plant dies back for winter.

Japanese knotweed will remain dormant beneath ground over the winter months but it will still be very much alive. It is best to avoid disturbing the plant’s rhizome structure as you may end up spreading the infestation. Ever wondered what Japanese knotweed rhizome looks like? The pic below shows the woody outer and the bright orange, carrot-like inner.

Japanese Knotweed Rhizome

Japanese Knotweed Rhizome

So what can be done over the winter months in order to eradicate Japanese knotweed?

Excavation & Removal of Japanese Knotweed in Autumn/Winter

Japanese knotweed can be excavated and removed from the ground and disposed of at a licensed landfill site. Screening the soil can be particularly difficult due to high moisture content from rainfall. Another option is to dig it out then bury in a specially constructed cell that will stop it from spreading and it will eventually perish within the cell’s impermeable membrane.

Herbicide Treatment OF JAPANESE KNOTWEED in Autumn/Winter

As far as herbicide application goes, there are products that can be used over the winter, however, finding the ideal conditions for treatment can be problematic.

Often the best plan for management of Japanese knotweed over autumn and winter is to segregate the area and restrict access. Clearly identifying it on a plan of the site as well as erecting warning signage should allow the Japanese knotweed to spend the colder months undisturbed. An eradication programme could start in spring once the weather improves as this will reduce the overall cost of the project.

If you suspect that your site is infested with Japanese knotweed then book a survey to get expert advice and a management plan for tackling this invasive weed. Get in touch here or call 01383 416 556.

IWA. Getting to the root of the problem.

Japanese Knotweed Eradication- it’s a marathon

Japanese Knotweed Contractors, IWA, achieve Which? Trusted Trader Status

Invasive Weeds Agency Ltd achieve Which? Trusted Trader Status

We have had a busy summer so far and our work continues across the UK on all manner of invasive species projects. Some projects of note are; Japanese knotweed eradication for Galloway Fisheries Trust on the Rivers Urr, Dee, Luce and their tributaries as part of the EU Interreg CIRB Project; two large-scale Japanese knotweed screening projects on development sites in Penicuik, Midlothian; and Japanese knotweed removal from a new business park in Aberdeen.

We are working hard for domestic clients at sites as far apart as Stroud in Kent to Avoch in the Black Isle (north of Inverness). Our straightforward and fair approach to pricing and customer service has led us to gain WHICH? Trusted Trader status. We are delighted to be part of the new WHICH? scheme as we feel that it will help separate the good, honest weed control companies from the many unscrupulous firms.

Treatment to achieve eradication of Japanese knotweed may take several seasons if the plants are deep-rooted and mature. This is one reason it is important to consider the credentials of the company you choose to appoint to carry out the work. There’s little worth in selecting a bunch of ‘experts’ who want all the money up front for a 3 year programme as there is a serious risk that they will take the cash and run, never to be seen again. if the treatment programme is not finished properly then it may lead to problems at a later date. Treatment is often a marathon, not a sprint. ‘Quick fix’ herbicide treatments have a nasty habit of leading to re-emergence of Japanese knotweed 2 or 3 years later despite the fact that the ground may have shown no signs of knotweed for a long time. We urge people to ask for references and case studies of previous work.

We look forward to receiving feedback from our clients regarding our service so that we can continue to raise our standards in order to offer the best value for money on services such as Japanese knotweed treatment and removal. Please leave feedback here.

If you are puzzled by the internet’s muddle of conflicting advice on Japanese knotweed eradication then please call our team now on 01383 416 556 for free advice or get in touch here.

IWA. Getting to the root of the problem.


Japanese Knotweed- Still Going Strong

Floating Pennywort

Floating Pennywort

It’s been a busy year for Invasive Weeds Agency (IWA). We’ve been tackling all of the usual invasive weeds (Japanese knotweed, giant hogweed, Himalayan balsam, rhododendron etc.) plus a few others that are less well known to gardeners and the public alike. Floating pennywort is a ‘new kid on the block’. As its name suggests, it is an aquatic weed. It is rapidly spreading throughout waterways in the south of England and it is causing severe damage to the sensitive water environment in Sites of Special Scientific Interest (SSSI) such as the Pevensey Levels. Control and eradication of floating pennywort can be achieved using excavation and removal followed by herbicide application to any remaining fragments. The process can be very time-consuming due to the delicate nature of the work in order to prevent the accidental spread of this weed.

Invasive Weeds Agency’s business manager, Graham Rudd, has delivered several presentations to the Royal Institution of Chartered Surveyors (RICS) on the subjects of invasive species management and common mistakes people make when dealing with Japanese knotweed. The presentations were well received and the feedback from RICS has been positive.

IWA are continuing to assist private, domestic clients across the UK. Our treatment programmes for Japanese knotweed eradication are more popular than ever due to our great prices, first-class service and HomePro insurance backed guarantees.

Japanese Knotweed

Japanese Knotweed

Got weed problems? Call us now on 01383 416 556 or message us here.

IWA. Getting to the root of the problem.


IWA Win EU Funded Contracts for Japanese Knotweed & Giant Hogweed

Giant Hogweed Control in Galloway

IWA Win Contracts for Control of Japanese Knotweed & Giant Hogweed in Galloway

We are delighted to have won two contracts to control Japanese knotweed (Fallopia japonica) and giant hogweed (Heracluem mantegazzianum) in Galloway on the Rivers Dee, Urr, Fleet and Cree as well as their tributaries. We were appointed by the Galloway Fisheries Trust (GFT) after winning competitive tenders for the work. The project is part financed by European Union’s Regional Development Fund through the INTERREG IVA Cross-border Programme.

2014 brings and end to the four year project and it will see Japanese knotweed and giant hogweed eradicated from many areas on the River Dee and Urr. Surveys have identified some infestations that have not previously been treated so this will give IWA the opportunity to make a great impact on reducing the spread of these non-native invasive species.

This is the fourth year that Invasive Weeds Agency have been successful in securing work with the Rivers and Fisheries Trusts Scotland  (RAFTS) based on our experience, skills and good reputation and we look forward to working closely with GFT this year. Much of the work on the Urr and Dee will take place close to the historic towns of Castle Douglas and Dalbeattie. The work on the Cree and Fleet is further west, en route to Stranraer.

If you know of any areas where invasive species are present on any of the waterways in Galloway, please get in touch so that these areas may be included in the treatment programme this year.

For further assistance with Japanese knotweed and giant hogweed, call one of our experts on 01383 416 556.

IWA. Getting to the root of the problem.


Japanese Knotweed Springs Up After Sunny Weather

Japanese Knotweed in St Andrews

Japanese Knotweed Shoots in Spring.

Spring is well underway! Long gone are the images of small creatures slinking out of their cosy winter sanctuaries and the once bare country landscapes are now bursting with life… For IWA, this is not a time of year to be resting on our laurels, in fact it we are now in peak season. This is the time when our old enemies like Japanese knotweed (Fallopia japonica), giant hogweed (Heracleum mantegazzianum) and Himalayan balsam (Impatiens glandulifera) rear their ugly heads. We are inundated with requests for surveys and site inspections, to give our expert advice on a wide range of non-native and invasive species of plants and animals.


After a relatively mild winter we noticed early signs of Japanese knotweed growth in February. The sunshine over the last month has prompted rapid growth and we have seem Japanese knotweed over 3 feet tall in Fife! Despite many weeds being visible, in most cases, it is still too early to implement a herbicide treatment regime. For householders limited to domestic herbicide products, it will still be a while before effective control of these species is achievable.


Now is the time to get the experts out to assess the situation and to put an eradication plan into action. After an initial enquiry by phone, email or social media, one of our team will attend your property to carry out a survey in order to assess the full extent of an infestation. A report will be written and a management plan will set out the treatment options available. When the plants are at the correct stage of their development, an eradication programme will begin in order to rid your property of the scourge of invasive species. Upon completion or the eradication works, we will issue an insurance backed guarantee.


So whether you are only just noticing the red, asparagus like stems of Japanese knotweed, or know that your property suffered from an invasive species last year, give us a call. Our BASIS qualified pesticide advisors, can advise you on the best treatment method for your site, and with our competitive prices and comprehensive insurance backed guarantees, you’re in safe hands. Call us now on 01383 416 556 or get in touch online here.

IWA. Getting to the root of the problem.

Japanese Knotweed Breaks Cover in Edinburgh

Walking the banks of the Water of Leith in spring time shows how diverse Edinburgh’s flora and fauna can be. Due to the river running through a variety of habitats ranging from farmland to a built-up city centre, it is no surprise that such a huge range of species can be found in close proximity to the capital’s main watercourse.

As a weed control company specialising in eradication of invasive non-native species, our main focus around the Water of Leith is Japanese knotweed (Fallopia japonica). Other invasives are present in abundance: Giant Hogweed (Hercaleum mantegazzianum); Himalayan Balsam (Impatiens glandulifera) and Buddleia (Buddleia davidii).

Japanese Knotweed beside the Water of Leith, Edinburgh

Japanese Knotweed beside the Water of Leith, Edinburgh

Japanese knotweed is a hardy perennial that can quickly colonise riparian areas. Its prevalence beside watercourses is well documented and it is a nationwide problem. Over the past 3 years, the Rivers and Fisheries Trust Scotland (RAFTS) have led a control programme on many of Scotland’s major waterways in order to reduce the impact of Japanese knotweed and other non-native plants. Hopefully this control programme will be rolled out in the capital in order to safeguard Edinburgh’s native species and to protect the city’s properties from this alien invader.

So what damage is Japanese knotweed causing to the Water of Leith and Edinburgh?

Some of the damage is immediately obvious and some less so. Due to the Japanese knotweed’s ability to increase in height by nearly 10cm per day during the spring and summer months, it can quickly tower over smaller, native species. As a result it will reduce the amount of light that reaches the native flora as well as restricting the native plants’ water and nutrient supplies. This ‘out-competing’ of native species leads to a reduction in biodiversity. This may not be immediately obvious to passersby, however, over time it will lead to a loss of native plant species and therefore a reduction in insects and animals that rely upon the native plants for their existence.

Perhaps the most obvious damage caused by Japanese knotweed is the disturbance or breaking of ground covering, e.g. the emergence of Japanese knotweed through paving. Generally, this happens when Japanese knotweed is growing beside a hard surface such as brick paving and the plant creeps beneath the brickwork. New shoots find their way up through gaps in the surface and eventually, as the plant matures, the brickwork becomes dislodged or damaged. This usually leads to some misinformation being passed around by any witnesses and it perpetuates the myth that Japanese knotweed will grow through concrete regardless of the thickness of the structure. Like many plants, Japanese knotweed will find the path of least resistance and work its way through small gaps or weak areas. It is not unusual for Japanese knotweed to emerge through tarmac as the surface is somewhat porous and therefore easily breached.

So if you are out for a stroll along the Water of Leith then keep your eyes peeled for Japanese knotweed and stay clear of it. It can be easily spread through disturbance of the rhizomes (underground creeping stems) or by cuttings of the plant’s stems. More information on Japanese knotweed can be found here. 

If you suspect that you have Japanese knotweed at your property in Edinburgh, contact us here or call 0131 441 2953.

IWA. Getting to the root of the problem.

Japanese Knotweed Edinburgh

Edinburgh Japanese Knotweed

Japanese Knotweed Edinburgh

The ancient city of Edinburgh, situated at the heart of Midlothian, has a long and colourful history. Some parts of Edinburgh’s history are worth remembering whilst others are best forgotten. Often, people in the capital will ponder, “what if it had been different?”, but it is impossible to change the past (sorry Dr. Who fans). One part of Edinburgh’s history that many householders and landowners would love to change would be the introduction of Japanese knotweed (Fallopia japonica) to the city’s capital.

It’s not clear when Japanese knotweed was first brought to Edinburgh. It was introduced to the UK in the 1830s as an ornamental plant and it was highly sought after for years. It is likely that Japanese knotweed was planted in gardens of the New Town as much for its aesthetic appeal as the status it afforded its owners.

Now, over 150 years later, Japanese knotweed has the opposite effect because people don’t want to know you if you have it on your land and it can have a huge impact on the value of your property!

We cannot change the past so we have to deal with the scourge of Japanese knotweed before it spreads further across Scotland’s capital city. Fear not, there are plenty of treatment methods available and Japanese knotweed is not impossible to eradicate if it is approached correctly. Methods of treatment include:

  • – Herbicide Spraying
  • – Stem Injection
  • – Weed Wiping
  • – Excavation & Removal (Dig & Dump)
  • – Screening
  • – Incineration
  • – Root Barrier
  • – Bund Creation
  • – Burial
  • – Encapsulation


If you suspect the presence of Japanese knotweed at your property in Edinburgh and need assitance, call 0131 441 2953 now to speak to one of our experts or contact us here.

IWA. Getting to the root of the problem.

IWA Present to RICS on Management of Japanese knotweed and Other Invasive Species

RICS Invasive Species Seminar, Aberdeen

RICS Invasive Species Seminar, Aberdeen

Invasive Weeds Agency Ltd were asked by the RICS to give a presentation on the management of invasive plant species at their annual CPD day in Perth on the 27th. This was the 3rd presentation of this kind that IWA have been asked to do in the last year and a 4th in Aberdeen has already been scheduled for this June. The presentations are delivered by IWA Co-Founder and Business Manager, Graham Rudd, who is a member of the BASIS Amenity Register (MBAR) with 8 years’ experience in the industry. These presentations focus on educating surveyors and other property professionals in best practice when it comes to managing the financial and environmental risks that can be presented by the presence of Japanese knotweed on a property. They comprise part of IWA’s ongoing CPD project aimed at raising awareness of the legislation concerning invasive species and the benefits of reacting quickly to issues of infestation. It was great to see surveyors from all over Scotland (the borders to Orkney -seriously!) attending the presentation.

With Japanese knotweed now being noted on home reports alongside other issues like damp and rot it is becoming even more important for surveyors to know what they are looking for and immediately know the correct course of action to remedy the situation. The reluctancy of banks to lend on properties with a knotweed infestation is well documented; Lentune Mortgage Consultancy managing director Stuart Gregory contacted twelve lenders to find out their views on the issue. He said: “There were only two or three that would really consider lending on properties with Japanese knotweed and those that would had strict criteria”. The  sale of a property falling through on account of Japanese knotweed is unfortunately an increasingly common occurrence and indeed a needless one; with the correct treatment carried out by qualified professionals the problem can be easily resolved. All work undertaken by IWA includes an insurance backed warranty to the value of £5 million guaranteeing complete eradication and with documentation of the treatment plan all lenders will be satisfied that the risk is being managed appropriately.

If you have found Japanese knotweed on your property or you would like more information on any of the invasive plant species that we regularly deal with then don’t hesitate to get in touch; you can either Contact us here or call us on 0845 676 9252.

IWA. Getting to the root of the problem.



Find out what qualifies Invasive Weeds Agency to assist you with your weed problem.

Japanese Knotweed Ruins House Value in Dudley

Japanese Knotweed Devalues Property

Japanese Knotweed Devalues Property

A 75 year old widow in Dudley  was shocked to learn that Japanese knotweed has caused her home to be deemed ‘worthless’ by mortgage lenders .

Jean Hale, a 75 year old widow from Dudley, has been refused a loan for essential home upgrades on account of a huge Japanese knotweed (Fallopia japonica) infestation bordering her property.

The lenders claimed that the Japanese knotweed would spread under Mrs Hales home and undermine the foundations causing structural instability and rendering the property unsellable.

The infestation is on land owned by Dudley council and Mrs Hale suggests that they should remove the knotweed or be forced to buy her house.

Councils up and down the country have issues with Japanese knotweed and cases like these where home owners are left with financial difficulties as a result are becoming increasingly common.

The whole story on the Japanese knotweed infestation can be read here.

There are many Japanese knotweed treatment methods that could be considered for a situation like this; herbicide spraying, stem injection, screening, rootbarrier, dig and dump. Given the fact that the council have an ongoing regime for the Japanese knotweed control then it is likely that they have been spraying it with herbicide. This may not have been the best choice of method as it will take longer to complete the treatment process than a method such as screening. Perhaps the choice of method has lead to the householder’s distress and the story being published.

If you are in a similar situation, a householder with a domestic Japanese knotweed problem, call our team of experts on one of our local numbers or on 0845 676 9252 or contact us here.

IWA. Getting to the root of the problem.

Japanese Knotweed Enjoys Mild Winter

Buds on Japanese Knotweed

Buds on Japanese Knotweed in Winter

IWA wish all of our clients and colleagues a Happy New Year and we hope everyone has had a positive start to 2014.

Who knows if it’s global warming or just a bit of luck but we seem to have avoided the bone chilling temperatures we were promised by the weatherman and everyone appreciates a mild winter, especially Japanese knotweed (Fallopia Japonica). The natural habitat of Japanese knotweed is actually volcanic terrain in Japan which means it’s certainly no stranger to seriously tough conditions above ground. The UK’s cold winters act to keep the year’s new growth at bay for a few months of the year but with conditions as agreeable as this; we could see the first sign of those unwanted asparagus-like shoots much sooner than expected. Throughout December and January, we have found buds present on Japanese knotweed rhizomes so the new shoots are not far from emerging.

The New Year is a time for a fresh start and whether it’s a house sale, an extension, a landscaping project or simply wanting peace of mind, everyone wants to start the year with a clean slate free from the threats of a Japanese knotweed infestation.

We know that everyone is feeling the January pinch and that’s why we’re now offering free surveys to all domestic clients in the Edinburgh and Glasgow areas for the whole of January! In addition to this, if suspect Japanese knotweed to be growing in your garden you can email us a picture and we guarantee to give you a response within 24 hours. This is certainly the perfect time to put your mind at ease and get the ball rolling to rid yourself and your property of this invasive threat.

For further assistance with invasive weeds from Scotland’s leading Japanese knotweed consultants and contractors, call Invasive Weeds Agency Ltd on 0845 676 9252, or our head office’s local number on 01383 416 556, or message us here.

IWA. Getting to the root of the problem.