Japanese Knotweed is an invasive plant with incredibly strong roots that could cause serious and significant damage to your property. The plant was introduced by the Victorians for ornamental purposes and it grows rapidly, by as much as 1.5 metres a month in the growing season from May to October.
Japanese Knotweed is not particularly widespread in and around Aberdeen but it does occur. Fortunately even where it is found there is no need to panic as the issue can be resolved, particularly if caught quickly and treated properly. You should not try to deal with the plant yourself but rather it should be excavated from the ground and disposed of under license. It is so invasively dangerous to buildings that Japanese Knotweed is a controlled waste that requires controlled disposal under the Environmental Protection Act, 1990. Any excavation will require extensive digging as leaving just a small section could allow it to grow back. It can also be treated chemically, although any chemical treatment would require to be applied over the course of several years to be effective. You will see from the methods involved that the treatment is likely to be time consuming and therefore relatively expensive.
Some surveyors make a note on Home Reports that they have not carried out an inspection for Japanese Knotweed as they are not obliged to look for this as part of the Home Report. However where the issue is evident to the surveyor they will comment on this. Whilst some mortgage lenders are reluctant to provide a mortgage on properties affected by Japanese Knotweed many in fact will still be happy to lend. Where they do lend they will look at the particular circumstances of the case and will wish to look for assurance that treatment works have been carried out/will continue to be treated as necessary and that a specialist guarantee has been issued.
If Japanese Knotweed affects your property another issue to check is the availability of buildings insurance for the property. The insurance company may attach a higher than normal premium to account for the higher than normal risk of damage that could potentially be caused by the invasive plant.
If you are aware of this issue affecting your property I would suggest that you deal with the matter as quickly as possible not only to prevent any significant damage to your property but also to avoid any impact on the value of your property or any potential difficulty in selling your property in the future. A further caution against ignoring the presence of the weed in your garden would be that allowing the spread of the weed into the wild could be an offence under the Wildlife and Countryside Act 1981 as amended by the Wildlife and Natural Environment (Scotland) Act 2011.
If Japanese Knotweed affects both you and your neighbours then, as with most neighbour issues, you would be best to discuss the matter amicably to reach a practical solution.