Japanese knotweed is from places like Japan and China, even parts of Russia as well. Throughout its native range, there are some kind of forces that keep it in check. These include things like volcanoes, for example, which is why we can't really kill it with fire in the UK. A single foliar application of glyphosate once a year was the most effective way of controlling Japanese knotweed - now supported by Welsh Government.
Since it was introduced to the UK in 1850, Japanese knotweed has gone from novel ornamental plant to rampant invasive species. Madeleine Finlay speaks to journalist Samanth Subramanian about the huge costs associated with finding it on a property, and Dr Sophie Hocking explains what the plant, and our attempts to control it, might be doing to the environment.. Help support our independent journalism at
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