Japanese Knotweed – What You Need To Know To Safeguard Property

Japanese Knotweed

Japanese Knotweed, what is a Japanese plant doing in the UK?

Japanese knotweed, also known as Fallopia Japonica, was brought to Europe as an ornamental garden plant in the mid-19th century.


It has become a bane for so many landlords and businesses including Network Rail.

This is highly invasive weed and grows well wherever water is in abundance.

It grows well around river beds and ponds.


When it starts growing in our gardens, that’s when it will become a huge problem for landlords and people living in the property.


There are legal and economic implications if Japanese knotweed is found in properties garden.

Japanese knotweed can cause structural damage to the property if not treated on time.

How To Identify Japanese Knotweed?

You can find if your area is affected using plant tracker (http://www.planttracker.org.uk/map/knotweed).

More information is present in rhs site at (https://www.rhs.org.uk/advice/profile?pid=218)

For an amateur gardener, it may not be very obvious, but there are some distinct features:

  • Leaves are shovel or heart shaped
  • Leaves form a zig-zag pattern up the stem
  • Stems have a bamboo-like look about them
  • Stems will also sport purple spots and are noticeably hollow when cut

In spring, shoots emerge from crimson-pink buds at ground level. They grow rapidly in summer, producing dense stands of tall bamboo-like canes which grow to 2.1m(7ft) tall.

In winter, it becomes dormant and stems dry out and turn brown.

What Are The Implications Of Japanese Knotweed?


Property can be structurally damaged as Japanese knotweed is a hardy beast. It can cause all sorts of damage including driveways, drainage systems and garden walls.

The underground roots and rhizomes can exploit the cracks/mortar joints and weaknesses causing structural damage to the building, if grown close to property.

Value of property will go down significantly. Not just that property of sorrounding properties could have consequences as well if it is not cured.


As a landlord, you are responsible for ensuring that it is not in your garden.

There is detailed guidance on how to prevent spreading at gov.uk.

Anti-Social Behaviour Powers

Individuals, businesses or organisations have a legal responsibility to prevent certain invasive non-native plants or injurious weeds on their premises spreading into the wild.


If Japanese knotweed is identified at an early stage, it can be cured in days or weeks.

It is best cured by a professional service after detailed analysis. At times it may take years to completely eradicate Japanese Knotweed.


Many lenders wouldn’t give a mortgage on properties with Japanese Knotweed. Few lenders will give mortgage provided there is a management plan to cure the Japanese knotweed is in place.

What Can You Do If You See Japanese Knotweed?


As a landlord, ensure that your garden does not have Japanese Knotweed.

If you see it growing in the neighbors garden, highlight the issue to them. Help them to cure so that it does not spread. You are in your rights to proceed legally so that you are not affected.

There are quite a few home owners who made claims against Network Rail and won some money towards damages. In this instance, Network Rail owned infested with weed.

Property investor:

As a property investor, when you go viewing properties, ensure that Japanese knotweed is not present in the property.

During winter, Japanese knotweed will be dormant.


The seller must mention in the legal pack if the property has Japanese Knotweed. Depending on your numbers, you may want to renegotiate offer price after including any cure required.


It is best to let nature run it course. Japanese Knotweed was thought as an ornament sometime ago, now it causing havoc in the UK.

It is not end of the world if you find Japanese Knotweed, be aware and take necessary steps to eradicate it.


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