Japanese Knotweed

Have heard this pernicious and evasive plant has been found in Willesden. It is said to be the biggest problem facing the construction industry today (though I suspect government policies and recession must be close runners). Japanese Knotweed is a tall perennial plant. The shoots start to emerge in late March/early April, are asparagus-like and are a red-green colour. As it grows through the summer the red colour turns into red speckles on an otherwise green stem. The weed can grow a metre a month and can cause heave below concrete and tarmac, coming up through the resulting cracks and damaging buildings and roads. Studies have shown that a 1cm section of rhizome can produce a new plant in 10 days. Rhizome segments can remain dormant in soil for twenty years before producing new plants.  It has to be removed by specialists.

1 comment:

  1. It is a pretty bad one for the construction industry. The trouble is unused plots of land are prime spots for fly tipping, so when japanese knotweed is dumped it quickly embeds itself and when left for any length of time can really just take over.