JAPANESE KNOTWEED
What is Japanese Knotweed?
Japanese Knotweed is a highly invasive plant that is fast becoming a pandemic in and around London. This plant is well known for its speed of growth at up to two centimetres a day, and how it takes over whole gardens at a phenomenal speed. Japanese Knotweed is listed in Schedule 9 of the Wildlife and Countryside Act 1981 (as amended), this act is in place to control the spread and prevent release into the wild, specific plants and animals that can have a devastating effect on the local environment (from ecological to socio-economic). Any evidence of a breach of the Wildlife and Countryside Act 1981 (as amended) will result in prosecution. Japanese Knotweed can look like a large shrub above ground but it's roots take a strong hold below ground and extend several meters. It's strongest assets is its ability to re-grow from tiny fragments (from 0.8g) of a root into a whole new plant. The main issue with Knotweed, is how invasive it is. This stems back to its origins where it grows naturally on the side of volcanoes in Japan. Due to its natural habitat being on top of solidified lava it has become a natural at punching its roots through everything from tarmac roads to concrete foundations. It is also well known for naturally taking control of its environment and bullying other plants out. This causes many issues from mortgages applications being rejected even if the weed is found on an adjacent property. Japanese Knotweed is classed as controlled waste and can only be disposed at certain licensed landfill sites, this also includes the soil the weed has been growing in.
Land owner responsibilities
Landowners are responsible for dealing with Japanese Knotweed if it is discovered on their land. Please see below how to identify and the best removal method for Japanese Knotweed. (See information from DEFRA)
How to Identify a Japanese Knotweed infestation?
Knotweed can grow at incredible speeds, here is its annual growth cycle: Commences growth in early spring Reaches one and a half meters above ground by May By June it can be three meters tall The weed then starts to die back between September and NovemberHere is what to look out for: Red shoots during early spring. A Bamboo like stem. Leaves grow in a zig-zag pattern along the stem. Green spade shaped leaves. White blossom flowers. Red or purple spots along the stem. Brown bamboo like stems left during autumn and winter.
Click here to view more images of the Japanese Knotweed.
How to treat and remove Knotweed
Our first bit of advice, is do not try to remove Japanese Knotweed! Due to its ability to re-grow from tiny parts of its root, we often find clients have removed the weed once and at least 6 more pop up in its place before then seeking specialist advice. Yes it is possible to dig it out however a three meter cube of top soil also has to be removed and disposed of at a licensed landfill. This is often expensive and impractical. Chemical control is currently the only proven effective way of winning the battle against the weeds spread and growth. Chemicals can be applied in many ways to the weed (spay, applied to cut canes, stem cell injection) but the most effective route to killing the weed is definitely the stem cell injection. This is the most effective because it inserts the chemical into the weed while it is still fully active and allows the weed itself to transport the chemical into its roots, and by killing the roots it reduces the risks of it re-growing and spreading unlike the other methods. There are some weed killers available in DIY stores that say they are effective against Japanese Knotweed, these can do the job, but the evidence shows that this is not effective and most people take 3-4 years treating the weed at least twice a year to get the weed eradicated with these off the shelf chemicals. Arboriculture specialists have access to much stronger controlled chemicals that are a lot more effective.We strongly suggest that you seek professional advice and quotes for removing the weed professionally.
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Identify Knotweed
