Dr Karen Bacon From the University of Leeds

We were lucky enough to sit down with Dr Karen Bacon from the University of Leeds to discuss her recent research into Japanese Knotweed. We were surprised to learn a different viewpoint on this invasive species that has been a topic of conversation within the property market for some time now.

1. How long have you been researching Japanese knotweed and what sparked your interest in the species?

I have been an active ecologist and researcher for over 10 years and my interests have always included invasive species; however, my work on Japanese knotweed is relatively new. The recent publication is my first on this species and I have been working on Japanese knotweed for about two years.

2. What drew your attention to the fact that Japanese Knotweed is a big talking point within the property market right now?

This came about due to conversations with colleagues in industry – particularly those in environmental consultancy and those working with councils.

3. Where did you conduct your research and how did you find these properties?

Unfortunately, the exact location of the properties is confidential. They have now been redeveloped. They were located in the North of England.

4. Did you work with any Japanese Knotweed removal specialists?

No, not directly. Members of the Property Care Association and members of the Royal Institute of Chartered Surveyors did complete our survey as part of the research project. The questions asked in the survey are provided in the supplementary information of the paper.

5. Do you feel your research, and subsequent findings, will act as reassurance to people with Japanese Knotweed on their property?

Hopefully, but there is a long way to go. The recent parliamentary hearing was a good starting point and we hope to continue to discuss the topic with key stakeholders in the near future.

6. Can you explain why Japanese Knotweed is NOT a problem for properties?

Japanese knotweed is no more of a problem than many other plants, and less than some. Like other species of plants, it can cause some problems and may exacerbate existing problems but it is no worse than other species. It is highly unlikely to be the primary cause of structural damage on well-built solid structures (like houses) and cannot grow directly through concrete. It may pose some problems for poorly built light structures (e.g. sheds) or garden paths – but again, no more so than many other plant species. Like many other plants, it will exploit even small cracks to grow through.

7. Can you tell us more about the negative impact that Japanese Knotweed can have on biodiversity and flood risks?

Japanese knotweed often outcompetes native plants in the UK and therefore disrupts local ecosystems. It grows early in the season and can therefore access nutrients before other species are beginning to grow and can shade out other species. It also dies back in the winter leading to potential increases in erosion and increasing the risk of flooding.

8. What is the key point you’d like readers of your research to take away?

That Japanese knotweed, which is certainly a biodiversity and ecological problem, is no more of a problem for solidly built structures than many other plants.

9. Do you think the weed will ever be effectively eradicated so that certain other species aren’t affected by it?

I think this is something that we do not have a clear picture of at the moment. We need to understand how successful control efforts have been over the last 20 – 30 years and that information is not currently readily available.

10. Are you planning on undertaking any further research into this particular weed? If not, what’s next for you in terms of research?

Yes. I currently have a research student looking into regeneration of Japanese knotweed and we hope that this will shed further light on how best to control the species.

If you have Japanese Knotweed on your property and want to sell it quickly to avoid paying for treatment then we can help. We will buy your property and put a treatment plan in place. All legal fees are included so you'll get a cash sum and peace of mind.