The Japanese knotweed locally here in Swansea has recovered very quickly from the frosts that knocked it back and made it brown and crispy! Now there is no stopping it and it is powering away, some of it having reached its maximum height with only leaves to unfurl and thicken up now.
At this property the Japanese knotweed was particularly tall with the crowns up to waist height and the growth over 2m above this over 2.5m height! The photo doesn’t quite do it justice but hard to do a selfie with such a large plant!
There were a few stems visible of treated Japanese knotweed over 11m from the house and this extensive and mature Japanese knotweed is over 20m away from the inhabitable space.
The vendor has lost 8 sales in the last 18 months due specifically due to the Japanese knotweed so they have contacted Knotweed Control for a specialist report in order to aid the conveyancing process and help the sale.
What happens once the report is ready next step depends on the requirement of the purchaser’s mortgage company but increasingly insist on a Property Care Association member undertake as least a 3 year treatment & monitoring programme with an Insurance Backed Guarantee in place.
The damage Japanese knotweed can do to property is often over exaggerated but it can and does stop house sales and reduce the value of properties and if left untreated it can spread quickly becoming increasingly established and expensive to treat.
This time of year it seems that you just turn your back and Japanese knotweed appears to have grown!
It goes from weak looking leggy lime green and strawberry coloured growth to robust stems with sturdy looking leaves of a deeper "fresh" green cover.Its fastest growth rate can be 10cm a day and is well ahead of other plants now many plants already reaching 1.5m here in Swansea.
The photographs below show the same stand of Japanese knotweed in Swansea city centre just 2 week apart illustrating the rapid expansion of the foliage after a period of warm weather!
Japanese knotweed (Fallopia japonica) is arguably THE most notorious invasive non-native species in the UK, gaining an almost mythical status. But, I hear you say, surely it is just a weed …… just a plant in the wrong place. So what IS the problem?
Japanese knotweed’s invasive nature
Since being introduced to the UK by the Victorians from its native Japan, Taiwan, northern China and Korea Japanese knotweed has spread far and wide and is now listed here by the Environment Agency in the top 10 worst invasive species as well as in the world's top 100 worst invasive species by the International Union for the Conservation of Nature (IUCN).
Our Welsh climate appears to be perfect for Japanese knotweed and with no natural pests that eat or weaken it has been able to put all its energy into growing and this with its naturally fast growth early in the season together us unwittingly propagating it through disturbing soils means it has grown and spread rapidly, VERY rapidly.
Fortunately the seeds are not viable in this county so it spreads by vegetative means only but as it requires only a tiny fragments of rhizome (modified underground stem) or crown material (where the stems mass together) as small as 0.7 gm (the size of a pea) to create a new plant it means it is all too easily spread.
Roads, canals, rivers and railways not only provide us with good connectivity but are also perfect vectors for species such as Japanese knotweed where rhizome and other viable material is easily carried from area to area infecting new sites. This along with fly tipping and poor or non-existent biosecurity measure on sites all contributed to its proliferation throughout Wales.
Japanese knotweed is tolerant of a really wide range of growing conditions. It can cope with soils with very little nutritional value, high contamination of heavy metals and hydrocarbons and thrives on disturbed land making it one of the most common species on post-industrial and brown field sites across Wales. Swansea is a real hotspot and is named as the unenviable capital of Japanese knotweed in the UK due to the huge volume growing in the city due to its busy industrial past.
Costs to the economy
According to the report in 2010 by CABI (Centre for Agriculture and Biosciences International) the total loss to the world economy as a result of INNS has been estimated at 5% of annual production, costing the British economy £1.7 billion per year and £0.13 billion to us here in Wales alone. In 2015 the then UK Environment minister George Eustice admitted that a national eradication programme of Japanese knotweed would be “prohibitively expensive” meaning only local control on a site by site basis really can be attained.
Construction sites & Planning Applications
Although some of the information is now out of date now out of date, the Environment Agency’s Managing Japanese knotweed on Development Sites: Code of Practice 2013 is still seen as the best guide. However each site and situation is different, requiring bespoke methods and solutions.
In an attempt at localised control, increasing numbers of local authorities have planning conditions attached to applications under the Town & Country Planning Act 1990 which require management plans and method statements for biosecurity controls, treatment and monitoring of Japanese knotweed and other INNS including Giant hogweed, Himalayan balsam and Rhododendron.
Problems of Japanese knotweed
Often claims of damage from of Japanese knotweed are exaggerated with extreme and serious problems being thankfully rare. Japanese knotweed finds the route of least resistance growing around obstructions and obstacles. However Japanese knotweed as many other plants takes advantage of weaknesses in concrete structures, foundations and joints working its way through cracks or gaps between prefabricated slab floors or where concrete has been thinly laid. However the plant grows very fast up to about 10cm at the peak of the growing season and rhizomes and crowns can force fissures apart in concrete and even bed rock once it is established.
Apart from the more obvious problems with Japanese knotweed on construction sites such as planning conditions, delays, increased complexities and costs there are a number of other issues. There can be a reduction in the value and saleability of property and land with Japanese knotweed as increasing numbers of mortgage companies won’t lend against properties with Japanese knotweed with underwriters get very twitchy unless Insurance Backed Guarantees (IBG) are in place.
Japanese knotweed is unsightly, can harbour litter and pest species with a potential for human health issues resulting in adverse publicity for the developer and future of the site if no dealt with appropriately.
Where Japanese knotweed grows near rivers there is an increased risk of flooding due to increased river bank instability and erosion. This also negatively impact on native biodiversity through silt in the water and eutrophication. Japanese knotweed all too often becomes a dominated monoculture species as it outcompetes and pushes out native species with no benefit to man nor beast.
Japanese knotweed Control & Treatment
There are generally 4 different control and combinations methods for Japanese knotweed; chemical/ herbicide control, physical control, biological control and a combined chemical and physical control method often referred to the bund method.
The best method depends on several factors including the size of infestation, time, money and space available, each having its advantage and disadvantages but all methods require care with ongoing vigilance and monitoring.
Ensure you employ a specialist in dealing with Japanese knotweed and other invasive species. The Property Care Association Invasive Weed Group (PCA IWG) provide consumers with a means of identifying specialist contractors and consultants who can undertake invasive weed control services which can help control and management of invasive species, offering the highest levels of technical knowledge and practical skill.
PCA IWG members are also part of the TrustMark, a scheme licensed by Government and supported by consumer protection groups enabling clients to find local trustworthy, reliable tradespeople operating to Government Endorsed Standards.
Chemical/ herbicide control
In situ herbicide control of Japanese knotweed needs to be undertaken by a suitably qualified and experienced operator as incorrect treatment can actually accelerate growth or cause temporary dormancy. A product suitable for the environment and location must be applied using an appropriate method, at the correct time of year in the correct weather conditions, following the UK’s National Action Plan (NAP) to meet EU Directive 2009/128/EC, the Sustainable Use Of Pesticides.
Excavation of the underground rhizome and root material can be a disruptive and expensive operation as rhizomes can grow down 3m and laterally 7m from each plant like a living iceberg. Excavated material is a “controlled waste” under the Environmental Protection Act 1990 but can screened to reduce volume to be landfilled, buried, burnt or chemically treated on site (see below). Each of these physical control options have specific requirements to ensure compliance with relevant area of legislation and needs to be approved by Natural Resources Wales before any works commence.
Specialised membrane or root barrier with recommended a 50 year guarantee can be used to stop vertical growth when burying Japanese knotweed on site or to pevent lateral infection for example where adjoining landowners are not co-operating with treatments. However, vigorous Japanese Knotweed can breach a poorly designed, installed root barrier or when it has been perforated or penetrated.
The Bund Method (combined physical & chemical/ herbicide control)
This method involves the excavation of contaminated Japanese knotweed soil and placing it on a specialised membrane/ root barrier where it can be left to grow undisturbed then treated with appropriate herbicides. This material, with care could be reused for landscaping on previously contaminated land on site.
Currently in the field research stage CABI (the Centre for Agriculture and Bioscience International) is undertaking extensive research into biological agents to help control Japanese knotweed. The most promising to date is a sap-sucking psyllid or leaf hopper, Aphalara itadori and a Leaf-spot fungus Microsphaerella spp although is appears biological controls alone will not eradicate Japanese Knotweed however could reduce its vigour and spread.
Japanese knotweed and the law
Professional advice should always be sought regarding the legalities of Japanese knotweed as it is a complex and relatively new and untested area of law.
However in a recent landmark case 2 private land owners in Maesteg successfully took Network Rail Infrastructure Limited to court claiming private nuisance as the Japanese knotweed on railway land interfered with the use and enjoyment of their land. The rail company were ordered to ensure the Japanese knotweed treated correctly as they had not followed good practice and then ordered to pay compensation due to the reduction in value of the properties. Network Rail might appeal but the ruling could have big implications for land owners with Japanese knotweed throughout the UK.
There are a whole host of other invasive non-native species that could be the next nemesis for the construction industry so there are plenty of specialists and researcher literally scanning the horizon to make sure they don’t become the beast that Japanese knotweed has turned into here in Wales!
Yes although Japanese knotweed is ONLY A PLANT, it can be very problematic and expensive to deal with so if you have it on your site make sure you get some good advice from a suitability qualified and experienced company sooner rather than later to save yourself costly delays and sleepless nights!
Invasive non native species (INNS) are recognised as one of the greatest threats to biodiversity globally and in recent years has started to be taken seriously as having wider environmental and economic damages estimated to cost being costing 5% of the world's economy.
The course will look at the main INNS plants in the UK, how they arrived, why they are so successful, their basic ID features, associated problems and benefits, current controls and treatment methods, relevant legislation, strategies and policies dealing with INNS, monitoring and recording campaigns and projects and future INNS which might cause problems.
This course is suitable ideal for amateur or professional botanists/ecologists both in the voluntary or ecological sector. Some prior knowledge of ecology would be useful.
Dates: 20th October 2015
Cost: £50 per person
Location: Crymlyn Bog National Nature Reserve Visitors Centre,
Address: Dinam Road Port Tennant, Swansea SA1 7BG
Grid Ref: Grid Ref: ST696945
Tutor: Jo Mullett
Provisional bookings can be made by telephoning 07790505232 or emailing firstname.lastname@example.org
Places will be confirmed closer to the date of the training.
Invasive non-native species (INNS) are recognised as one of the greatest threats to biodiversity globally and in recent years has started to be taken seriously as having wider environmental and economic damages estimated to cost being costing 5% of the world's economy.
The course will look at the main INNS in the UK, a look how they arrived, how and why they are so successful, their basic ID features, problems and benefits they bring, current controls and treatment methods, relevant legislation, strategies and policies dealing with INNS, monitoring and recording campaigns and projects and future INNS which might cause problems.
This course is suitable ideal for amateur or professional botanists/ecologists both in the voluntary or ecological sector. Some prior knowledge of ecology would be useful but not essential. Jo Mullett has over 20 years' experience in the environmental sector. She has worked for a small local environmental charity as a Waste Education Officer, a national conservation charity as a Field Teacher, as a Biodiversity Officer for a local authority and now runs two companies Knotweed Control and About Wild Wales, combining INNS control consultancy with biodiversity awareness and conservation working with the general public, land owners and community.
Centre: Margam Discovery Centre / Canolfan Ddarganfod Margam
Tutor: Jo Mullett
Dates : Friday 29 May to Sunday 31 May
Level: Open for Everyone
RESIDENT (SOLE OCCUPANCY): £160
RESIDENT (SHARED ROOM): £130
Provisional bookings can be made by telephoning the centre on 01639 895636, by e-mail at email@example.com or by completing the online form on the FSC website: www.field-studies-council.org You will then be asked to complete a booking form, located within the relevant brochure or available to print off from the FSC website.
Having already attended and passed the Property Care Associations (PCA) Qualified Technician course (PCA QT) back in March 2014, I have just found out I am now a PCA Certified Surveyor in the Control & Eradication of Japanese knotweed which is another step towards attaining PCA membership! Some mortgage lenders insist on membership. The next hurdle is to be trading full time for 2 years but in the meantime I can apparently apply to become an associate member. Frustrating since I have been trading part time since 2011 but rules are rules!
#Japanese #knotweed is all over the #BBC http://bbc.in/1xnlzM4 for some reason today, talking about new Home Office Guidance of using #ASBOs to get it treated where it is a problem and control its spread. In Knotweed Control's experience prosecution will be highly unlikely due to many factors including often local councils, who are supported to enforce this legislation will be in breach in many instances themselves and also all current legislation regarding Japanese is rarely enforced.
There is so much paranoia about the plant and mortgage lenders and insurers are over the top with their demands for guarantees. Diligence, persistence and care is required in the treatment and reduce the risk of spread.
It still surprises me that people here in Swansea, the UK capital of knotweed people don’t do more to control it on or near their land, they only seem to be made aware once a potential buyer has a mortgage turned down.
Jo Mullett, owner of Knotweed Control