While Japanese Knotweed is actually quite an attractive looking plant, it is important not to be fooled by its beauty as this destructive plant costs Britain an estimated £165 million every year. It has even been listed by the World Conservation Union as one of the worst invasive species in the world. Due to the fact that it can squeeze through masonry and concrete, it can drastically reduce the value of your property. In recent times, an increasing amount of banks have been refusing to provide mortgages for properties affected by the invasive plant. Homeowners must remain alert and treat any suspect plants immediately because the invasive weed is capable of devaluing a property by tens of thousands of pounds. Luckily, all this potential damage can be avoided by knowing how to identify Japanese Knotweed and having the plant treated before it can cause any substantial damage to your property.


The beautiful but destructive plant grows at a phenomenal rate of over 3 feet a week so its appearance is prone to change. The plant can grow up to 3 to 4 metres in height and can spread 7 metres in any direction so it can quickly grow out of control if left untreated. As the plant decomposes in winter, spring is a desirable time to treat the plant as soon it starts to re-emerge.

The invasive weed will initially be spotted in the form of pink and red buds shooting up from the ground. The weather in spring has quite a significant impact on when the weed will first re-emerge but the plant will normally first be noticed by homeowners between March and April. Last year, this emergence appeared two months later than normal due to unusual icy and snowy weather. However, spring has been significantly warmer in 2019 and the plant has already started to re-emerge across the U.K.

In its early stages, the destructive weed has been likened to asparagus spears. Due to the fast growth of Knotweed, these spears will quickly turn into thick and hollow canes in a bamboo like structure. These canes are quite distinctive as they contain a pattern of purple speckles. As the weeks go on and the plant continues to increase in size, green leaves will start to unroll from the canes. These leaves contain a zig zag pattern and are shaped like a pointed love heart.   



Japanese Knotweed is capable of damaging more than just your property. If you allow Japanese Knotweed to spread onto your neighbour’s property, this can be classified as a public nuisance and you could be prosecuted under civil law. It is strongly advised that you do not attempt to treat your Knotweed problem yourself as failed treatment can do further damage and make the cost to treat even more expensive.

If you notice a suspicious looking plant on or anywhere near your property, then don’t hesitate to contact a professionally trained Knotweed surveyor for treatment of the invasive plant before it grows out of control and seriously affects the value of your property.   

By Jake Ryan of Wise Knotweed Solutions

Japanese Knotweed in the garden, in tarmac and early shoots