Japanese knotweed was initially indigenous to Japan, China and Korea – it has now spread worldwide, and the World Conservation Union has list it as one of the world’s worst invasive species. Read on below on the spread of Japanese Knotweed worldwide!
Phillipp Franz Balthasar von Siebold, the physician and botanist, bought Japanese knotweed to Europe. Von Siebold travelled across Japan for 8 years before returning to Europe, bringing hundreds of samples with him, including Japanese knotweed. A specimen was donated to the Botanic Gardens in Kew in 1850 and from there, the plant has spread. Japanese knotweed is now found UK wide, with the weed spreading thanks to the rail and water networks. Also, Japanese knotweed is also found in Ireland, with the first record of the plant found in the country in 1872.
Japanese knotweed is still most prevalent in the UK, due to the plant’s popularity in the late Victorian era in themed gardens.
Japanese knotweed has been introduced (through various means) to 42 of the 50 states. It is currently not located in North Dakota, Wyoming, Nevada, Arizona, New Mexico, Texas, Alabama and Florida. The plant is currently documented by the National Resources Conservation Service to ensure that it does not spread more widely.
The weed is found in all but two provinces (not Manitoba or Saskatchewan). The infestation rate is lower than in the UK, as Canada will use strong herbicides closer to waterways to help aggressively treat knotweed.
There have been cases of knotweed in other countries, including New Zealand, Germany and a number of countries in Scandinavia. Many countries will stop knotweed entering the country at the border to ensure it is not planted and will not grow in an uncontrolled way.
Have you found Japanese knotweed on your property? Not sure if you are able to make a claim? Who is legally responsible?
If you need help identifying Japanese knotweed, you first must know that it will look different depending on the current season.
See what treatment options are available for residential properties.
If you think that your neighbour has Japanese knotweed, and may potential spread to your garden, here is a step-by-step guide for tips on what to do next.
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