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?