Japanese Knotweed: A Menace to Homeowners

Knotweed problems

Japanese knotweed is a highly invasive, bamboo-like plant that currently occupies most regions of the British Isles except Orkney.  It is an extremely hardy plant that can cause damage to walls, foundations, gardens, paths and driveways.  It often prevents homeowners from remortgaging or selling their property and it is extremely difficult to eradicate as the roots go extremely deep and discarded cuttings will re-root themselves.

Some banks and building societies will not lend money on a property that has Japanese knotweed, even if the plant is as far as 30 metres away from the building, or even growing in a neighbour’s garden.  There has been a case recently highlighted in the Daily Mail where a homeowner from Cornwall tried to remortgage and was turned down flat by Santander because he had knotweed in the garden.

If you are buying a property, it is important to know what the plant looks like.  If you end up buying a property that has Japanese knotweed in its grounds then you’re in trouble, as there is very little chance of legal redress.  It would have to be proved that the seller knew about the weed and took steps to conceal its presence – even then, there is no guarantee of winning any compensation in a court of law.

Another thing to be aware of; is the fact that Japanese knotweed is no respecter of boundaries and if a neighbour’s garden has it, then it will very soon be appearing in your garden too.  Unfortunately, if your neighbour chooses to do nothing about it, you have very little opportunity to force their hand.  The principle law relating to Japanese knotweed is covered by the Wildlife and Countryside Act (1981), which states that ‘if any person plants or otherwise causes to grow in the wild any plant which is included in Part II of Schedule 9, he shall be guilt of an offence’.  The main problem with this quotation is; can a garden be really classed as ‘in the wild’?
So if you’ve got knotweed and it’s affecting your property, how do you get rid of it?  Well, there are many specialists out there who will either get rid of it by a combination of excavation and herbicides, but of course this doesn’t come cheap; £100 per square foot is the benchmark figure.  However, help may be at hand from a more natural source.  A psyllid (family of jumping plant lice) that feeds on the sap of Japanese knotweed is being introduced to the South of England.  This insect, that was imported specially from Southern Japan, only lives for a few weeks but will lay thousands of eggs in its lifespan.

Failing everything else it is edible and is apparently a good source of vitamin C.  It can be used to make jam, fruit pies, soup, broth, ice cream and stir fries.  Seemingly, Japanese knotweed also has medicinal properties, containing high levels of resveratrol; accordingly it can be used to control a diverse number of complaints from athlete’s foot to sexually transmitted diseases.  Japanese research also suggests that it could be suitable for the control of tumours and cancers.