Thursday, 1 July 2010

Japanese Knotweed

When my good friend Karen O was house hunting throughout North London, she was turned down mortgages on several houses just because a certain plant was growing in the garden. Japanese Knotweed was brought to the UK in the Victorian era and has since become the most invasive weed in the country. I viewed one house with Karen where we discovered Japanese Knotweed growing in the garden, it appeared that the house was subsiding as a result.

Knotweed can grow through walls and concrete and in really poor conditions. It can grow to 13ft and is virtually impossible for the average gardener to control. East London was so rampant with the weed that the 2012 Olympic site has - according to this website - been left with at least 70m weed eradication bill.

Japanese Knotweed

You've worryingly probably seen it at the side of railway tracks at some point.

I became completely obsessed with this weed last year - I thought it extraordinary that a plant could literally destroy buildings and be virtually impossible to remove. Disposing of the weed incorrectly even carries a 2 year prison sentence!

It would appear that in Japan, the spread of Knotweed is controlled by a few natural predators. Including a Psyllid - a little bug that feeds on sap from the knotweed ultimately killing it. There's a trial to be conducted in the hope that this bug will not kill other plants native to the UK at the same time - See here



  1. Is this a two year sentence in the UK? Thats unbelievable. Although this is a very bad thing to do let alone irresponsible, people who have hurt children or others get a smaller sentence?

    Knotweed is becoming frequently visible in cooking features and online recipes where people are choosing to cook the plant whilst keeping it under control. To me this sounds a great idea, however control is key here!


  2. Knotweed can be like a recurring nightmare for anybody who owns a house or even a small garden, especially if some great amount of time has been spent on getting rid of the weed, but then it's back the next season, and even spreading quicker than ever before

    Btw, couldn't help but notice the first link is no longer available.