/ Home & Energy

Are weeds killing your mortgage chances?

The list of plant nightmares for your house can be quite extensive. And now some people are finding they can’t get a mortgage if Japanese knotweed has been found in their garden or even close to the property.

There are Leylandii conifers that block out your light, ivy plants pulling out your mortar and tree roots clogging up your drains. But Japanese knotweed is the one to watch out for.

Japanese knotweed looks a bit like bamboo or dogwood. It’s hardy, perennial (it lives for more than two years), and can grow to over two metres tall. It was introduced to the UK in the mid-19th century and, because it’s invasive, difficult to kill and nothing really eats it, it’s now widespread.

Weeding out the issue

Keen gardeners will know all about dealing with difficult weeds such as bindweed and ivy – but Japanese knotweed is devilish to get rid of. The Royal Horticultural Society even calls it a ‘thug’!

The creeping roots of the Japanese knotweed are extremely difficult to eradicate and it can grow back from just a centimetre of root. However, it can be killed by repeated treatment over several years with the strong weedkiller glyphosate.

If you call in the professionals it can be a very expensive job – the Royal Institution of Chartered Surveyors (RICS) estimates it can cost up to £5,000 to use other techniques like root barriers to stop it spreading while the weedkiller is working. If the knotweed is creeping in from nearby land, you’ll need a co-ordinated attack.

But what damage does it do to your house? The guidance from RICS talks about drains getting blocked by roots, patio slabs being disrupted, and buildings with shallow foundations (like garages, sheds and conservatories) being undermined. It says that more dramatic damage to buildings is very rare and exceptional.

Knot a problem?

So is Japanese knotweed a big problem when it comes to selling your house? You may have read about Peter Gingell over the weekend, whose house sale fell apart when his buyers discovered Japanese knotweed in his garden. Some mortgage lenders are even turning down mortgage applications on properties where knotweed is present.

So even if Japanese knotweed can really cause uninsurable structural problems, surely a blanket ‘no’ policy to mortgage lending isn’t the best solution? Our mortgages expert Marie Kemplay says:

‘The situation regarding knotweed is quite confusing, and although organisations like RICS have produced guidance for mortgage lenders, there are no clear cut rules. Some lenders will not offer mortgages if Japanese knotwood is present on your land whilst others will consider it providing there are some guarantees in place.

‘But one general piece of advice is, no matter how tempting, not to just rip it out of the ground yourself. You need to get professionals in otherwise you may find it difficult to prove you have taken appropriate action to get rid of the problem.’

Have you had any plant problems with your house? Would finding Japanese knotweed in the garden put you off a purchase?


So it makes sense to completely remove all of the plants before you try to sell your house. If I was buying a house I would only worry if I thought they would effect the mortgage – I’m not sure it often happens that a mortgage is actually stopped due Knot weed

bellaboo says:
1 May 2013

we have just had a mortgage application declined after valuation on a property that “apparently” has knotweed on it…

we have scoured the place and not seen ANY evidence of it, not even something that resembles it, and we haven’t even been given the opportunity to get a horticultural expert in to identify the supposed knotweed, just a flat out decline!
we feel there is a high likely hood that the valuer has misidentified “japanese knotweed” and cost us our mortgage, but we don’t even have the chance to find out WHERE he thinks he saw it, and double check…

bellaboo says:
5 May 2013

just an update- we had a survey done by a japanese knotweed specialist, and it turns out that there ISN’T any present ANYWHERE on the grounds, or even anything that could be mistaken for it, but a surveyor not knowing what he was talking about in his report caused a decline of our mortgage!

Jan says:
25 May 2013

Well it has just stopped the sale of my house. I know the plant, most of it is in a neighbouring garden and I have been treating it for over 10 years to the extent that I have eradicated to the main extent.

It seems to be this neurosis is like the earlier days of trees near to houses…. irrespective of the size or behaviour of tree root sizes …. It makes me absolutely sick that mortgage companies who are supposed to issue mortgages will use every method in the book to deny mortgage lending … and thereby economic growth… Its a bit like bankers not allowing people to open bank accounts or insurance companies not paying out on insurances…. the place has gone mad… Just glad that from this year I wont need a blinking mortgage…. and I can get shot of the evidence before the next chump with his ladder and tape measure waddles around my premises…… fume!

bellaboo says:
25 May 2013

thats just the thing isn’t it! if you eradicate any sign of it before the pen pusher comes around, all would be fine, so they are only encouraging people to hide things, which makes it MORE of a risk to the bank!
If they would just accept the insured eradication program as part of the mortgage stipulations, then it would be dealt with, and people wouldn’t need to try to hide it!

in our case, there just was NO knotweed anywhere but the valuer made it up to red line our mortgage!
we proved him wrong,with a survey from a weed expert ,so are moving forwards once again with the house sale, but its all just jolly ridiculous…

JJ says:
31 July 2014

I have a £200,000 plus house on the market that I have sold…everything going well we have bougtht another property etc…the buyers thrilled wth this house then valuer comes says house if “perfect” but mentions on vauation that on neighbouring waste land there is knotweed…caused immediate termination of Mortgage by buiding society nearest plant o my boundary is 10 metres and we have a huge wall and driveway in between…its devastating!.. as everything has now fallen through so it does happen and is happening more and more..there needs to be talks between lenders and government to stop blanket policy on this weed and some form of grading system developed as my house according to surveyor for knotweed is not at risk!

bellaboo says:
13 September 2014

I just wanted to update on my above comment.

After calling B*** S*** on the valuer, we argued our case, and hired a plant expert to do a survey to PROVE there was NO japanese knotweed on the property or anywhere near it!

The surveyor was sorely mistaken, and there was nothing here that could even be mistaken for possible knotweed, so he had no idea what he was talking about.

we got our mortgage back on track and have been living in our home for over 6 mths now!

Coco says:
23 January 2015

It can cost money and major stress. I’ve even been told by one surveyor that colleagues actively look for it. Oh I had 1 report that demanded I get a survey undertaken by a specialist company, then sell you an eradication plan costing £kkks.

If a vendor omits information or lies about a property being affected by Japanese knotweed on the TA6 Property Information Form (since 2013) you could be in breach of the Misrepresentation Act 1965. And yes depending on the mortgage company they can and do refuse mortgages if knotweed is on site or put barriers in place requiring surveys, monitoring and insurance backed guarantees or withholding money until controlled

I am afraid this is not an uncommon story. I have had to survey 2 properties where mis-identification was the cause of much stress and sometimes when surveyors know an area is a hotspot for knotweed or if the garden is overgrown they will use the “pro-cautionary principle” but a flat refusal is just bonkers.

Mark says:
21 August 2016

What have you done. I have had a similar experience! How do I get my neighbour to deal with the infestation in their back garden not mine

Unfortunately, it is not illegal to have Japanese Knotweed on your property, but it is illegal if you allow it to spread onto someone else’s property. You can educate your neighbour on the potential structure damage the knotweed can cause.

[Sorry nad1409, we can’t allow you to post links which could be promotional. Please ensure your comments adhere to our community guidelines. Thanks, mods]

Early identification and treatment should be the priority for home owners to contain the weed and costs associated with its eradication or control. Costs for eradicating Japanese Knotweed when it has spread can be considerable and the process can take some time to complete. Lenders are risk averse in this economic climate so it is increasingly likely that where Japanese Knotweed is identified as a problem, remediation will be required. Also, where construction work, such as an extension to a property is planned, soil containing Japanese Knotweed should be completely removed!

Charlie Douglas says:
13 September 2012

If you can bring in a specialist contractor to deal with the Japanese knotweed who offer a guarantee for treatments then a bank should, in most cases, offer a mortgage.

As mentioned in the article, RICS have recently put together a paper on Japanese knotweed to try and encourage banks to lend on properties affected. It is becoming a larger and larger problem, but thankfully, people are becoming aware of it. It was featured on The One Show recently, newspapers regularly have articles. Argyll and Bute Council are creating a Code of Practice for it too.

The more that we do to spread the word about Japanese knotweed the easier it will be to stop it causing problems.


Susie B says:
13 September 2012

Finding Japanese knotweed would definitely put me off buying a house a bit : but then if I ever found it, I would negotiate with the sellers of the house on the house price, and use it to lower my offer. It may be that it would have to be treated in order to get the mortgage, so then I’d just agree with the sellers that I’d buy it once the problem is sorted out. Job done!

My next door neighbour’s garden has been overrun by Japanese knotweed but they don’t appear to mind as they never use their garden.

l only bought the house in December, so there was no sign of this plant but I doubt it would have put me off because, until recently, I’d never heard of Japanese knotweed.

I live in a terrace house, so the neighbours garden is very close to my property. Should I be worried by this stuff as it’s now at least 7 or 8 foot high.

David Knight says:
13 September 2012

There are a number of plants that cause damage to buildings. Budlea is one of the most common, some gardeners call it the butterflies friend but it can self seed in the smallest areas, grows quickly and the root ball can cause large cracks in brickwork.

My boss has been trying to get rid of knotweed at the back of his garden for a number of years, he was told that he would not be able to sell his house because of it. I know he burns it but it keeps growing back. I will tell him to contact the RICS after reading this article.

We have this on a council-owned piece of land next to our front garden. Every year it grows around 10′ long through the railings and we have to chop it back 3 or 4 times each summer so we can get our car off the driveway. We report it to the council every year but they refuse to do anything about it, although I’ve been told that it’s on some sort of restricted plant list that the council are responsible for. I hadn’t heard about the problems with mortgages before. Maybe when we come to sell and can’t get a buyer we should sue the council. The most annoying thing is that we live at the end of a cul-de-sac where nobody ever walks, but if our hedge grows more than about 6″ over the pavement we get a letter from the council telling us it’s causing a nuisance and threatening us with prosecution if we don’t cut it within 2 weeks!

I have just had a bank turn down lending on a property, as the survey company said there was a previously case on the street!! They haven’t even gone to view the property, the bank has flat out refused to lend on the advice of there surveyors.

Very frustrating.. as I don’t even know where the infection was (a neighbour) if it has been dealt with.

I have contacted the council… no record of anything on the street

Contact the environment agency…. only can help if Japanese Knotweed is on the property.

Bank doesn’t know where the outbreak was, and I am trying to contact their surveyors

Mark says:
21 August 2016

Where are you now?

Nigel says:
7 April 2013

We bought an old deserted farmhouse to renovate and the front garden was full of the stuff. My research advised that spraying with Glycophosphate was the most reliable method of eradication – and to never just pull up healthy plants. Initial spraying killed the visible plants, and it took about 5 years to completely eradicate them.

Himalayan balsam is the biggest problem now – thankfully that can safely be pulled up, but care has to be taken when disposing of the plants.

Despite what you may read on many websites, the weedkiller is glyphosate and not Glycophosphate. Simple mistakes like this are often a good way of deciding which advice is worthwhile using.

Best of luck with the balsam bashing.

From the Royal Horticultural Society website:

A note on glyphosate May 2016: After reviewing glyphosate, the European Parliament has given the go ahead to relicense it but proposes disallowing certain uses such as public open space and restricting it to professional use only. The final resolution will be decided by national authorities this summer which may mean the withdrawal of glyphosate-based weedkillers for home gardeners in the UK. Check the RHS website for further updates.

lisa says:
10 May 2013

I think WHICH should really investigate this issue and write a more thorough and informed article about it. There are many different types of treatment i.e. glycophosphate and tordon, etc. and it is important to know what to look for in a reputable company i.e. being a member of Property Care Association, etc. This information may help a consumer who is looking to deal with the problem in a proper way, which ensures they can sell their property on. There are some cowboy companies around and this information would help people to make informed decisions.

It might also be helpful to advise consumer to request that this is looked for in their surveys and what is possible if someone moves into a property to discover it there even if surveyors and bank valuers have missed it or if people have been duped by the previous owners. Again, important information for a WHICH magazine reader.

The PCA came in for a great deal of criticism on a Conversation (search for ‘dodgy damp advice’) about their members’ advice on damp treatment. Some of this was from representatives of companies that are not members PCA, obviously intent on destroying the reputation of PCA. What I did learn was how important it is to try and understand a problem before calling in the professionals.

PCA is a trade organisation and I think its fair to say that trade organisations are primarily there to serve the interests of their members. From the consumer’s point of view, you need to find out what a trade body will do if you are unfortunate enough to have a dispute with one of their members.

As I said before, there is no such thing as ‘glycophosphate’.

Steve says:
14 June 2013

I’m in the process of buying a house which has Knotweed growing right behind the rear garden fence, I’ts about 10 ft high and the land is owned by the local council.The seller told me about the weed and she was quite open about it and said that the council had treated it in the past, but I did not realise that some banks won’t lend because of it. I have contacted the council who say that they will get it treated, but I have put a hold on the transaction. Does anyone know which banks would be willing to lend.

mary says:
9 July 2013

get in touch with your local or any estate agent they will have a list of lenders willing to take on the property with japanese knotwood.

Nigel says:
22 November 2013

My daughter bought a new build house 5 years ago. When moving in, Japanese Knotweed was found 3 feet from the side wall, bottom of garden & on adjacent land. The developer contracted clearance to a specialist, who sprayed with piciloram & repeated 12 months later. After 3 years he issued a certificate of clearance but no extended guarantee.
My daughter has to sell, due to health problems and move into a small apartment. Her estate agent advises that she will have to drop the price to sell!
My question is – can one obtain & pay for insurance say for 20 years? If any one knows a company that does this, I would be grateful to hear as it may satisfy the purchaser & mortgage company. Thanks.

I had a valuer come round today for a remortgage and he said there was Japanese Knotweed growing in the land behind my garden which is owned by National Rail. It is about 7 metres away and he said it will likely result in my flat being rendered worthless and the lender not agreeing to a mortgage. I’ve contacted NR but I also think it’s started growing in the communal garden which adjoins mine.I’ve been here 5 years and I’ve never seen it before now, it’s not in my garden to my knowledge. I’ve told the management company as it’s share of freehold but on top of being extremely worried I don’t know who’s responsible. I was also looking to sell the flat next year but doubt anyone will buy it now


I have a similar issue in that I have knotweed on land around my first floor leasehold flat. I am trying to sell it (after a sale fell through a couple of years ago because of it) but so far no one wants to touch it when they know about the knotweed. Like you, I am struggling to find out who is responsible for treating it – my freeholder said he is treating it himself but that doesn’t provide me with the insurance and treatment plan mortgage lenders want, even with it, some are still refusing mortgages. The knotweed is also in the garden next door so it looks as though it’s come from there, but I was told by a solicitor that because I don’t own the land, I can’t make a claim on them. So I am left with a flat I can’t sell, and no power to do anything about it.

My daughter bought a new build property in 2008 and there was a plant in the side passage which we joked was Japanese Knot Weed – B Hell it turned out to be true. Having done instant research on the web, I contacted “LandTech of Worc,s” whom I put in contact with the developers – they met the cost of treatment with “piciloram” over a three year period – this has been effective. However due to illness my daughter is contemplating selling and the Estate agents were most negative – “it will be difficult to sell and the price will have to be dropped”
LandTech put us in touch with an insurance company which covered the re-damage to the property for 25 years. It did not cover treatment for re-appearance but LandTech agreed to cover this for the same period.

Let me tell you it is a shattering experience for someone who is extremely disabled and ill.

Should you want more feedback, please come back to me.



Previous Message

jodie says:
15 October 2014


what was the name of the insurer? did you manage to sell and did the new owners manage to get a mortgage on it?
I’ve found a property where the neighbouring garden has knotweed (there is a lot of scrubland/woods around the properties). They have a plan in place with a specialist for the next 3 years and one treatment has already happened.
Wondering whether this would affect the mortgagability of the house.

My daughter had mortgage approved ,contracts came in post to exchange valuation done,she rang mortgage company to ask about something and they said sorry mortgage offer cancelled due to this weed,surely they should have been informed before it got to this stage,

Extra to above email the house is a new build soil has been treated and removed a wall and a fence at bottom of garden,the weed isnt even on property

Sue says:
16 June 2015

has anyone been succesful in getting a mortgage offered on a property with JKW with a care plan in place ?

This has all the hallmarks of a racket, but for more dangerous because it has grown into the professions that once looked after people, but now concentrate on their power to ruin people’s lives. A newspaper report said that one person has even killed himself because of knotweed in his garden. (Google “knotweed suicide”) Myths like “Knotweed can grow through concrete” abound (it only grows through cracks — so will grass.)

Members of these professions will slavishly follow rules that makes them money, and the government gets 20% on top, so turns a blind eye. It is a sort of Ponzi scheme in reverse. At someone else commented, the PCA is a trade association, designed to increase the income of trades, not to care for customers’ property, as its name suggests. Obviously if gardeners can get wages running into thousands of pounds (rather than £10 to 20 an hour) they would be foolish (albeit unethical) to take it. Similarly mortgage lenders and associated professions such as conveyance lawyers get more money (+VAT) if house sales fall through. The customers are still there to fleece for the next one. The more stressful house sales become, the more money they make, It doesn’t matter that people’s health is damaged, just as long as the fees (+VAT) keep rolling in.

There must be (ethically rather then just legally) honest people in the professions, and hopefully Which? can point them out for subscribers, but like trying to find some indigenous plants in an English garden, it could be very difficult.

I smell a racket too here. I had a surveyor come round yesterday for a valuation on behalf of Barclays/Woolwich, he asked what was behind the house. I told him it was a stream, I told him the name and he said ‘Ah that one, it’s full of Japanese Knotweed’, then he started to actively look for any growths in our garden and moving about plant pots. When he found ONE, it was almost with some satisfaction, he excalimed ‘Found it!!!!’.

Have just read the report this morning which he has submitted to Barclays/Woolwich stating,

“Japanese Knotweed is present within 7 metres of habitable space. The property is not considered suitable securityuntil remedial work is undertaken by a PCA registered company covered by a minimum 10 year insurance backed guarantee which is property specific and fully transferable,”

This is really frustrating as it has taken nearly 2 years to get to this stage of the buying process for me – I shall nervously wait to hear what Barclays/Woolwich have to say. Should state I am only looking for a 50% LTV.

This link from the Rockefeller University in the USA has been brought to my attention. It says is all really:


It seems that all this is just a legalised protection racket. This link from the Telegraph shows how far these people will go:

The plant of hate in Arizona this week is Tamarisk: