Welcome to my world..............

Monday, 6 August 2012

Here's one I missed...

Having taken photos of the Himalayan Balsam on the canal cut at Langthorpe, I actually missed another Asian introduced pest plant, which is only now coming into leaf.  The naked spikes of the Japanese Knotweed are plainly visible in the second photo on 27 July, but these are now in leaf and rather more noticeable.
Japanese Knotweed surrounded by Himalayan Balsam

This is another species introduced from Asia as an ornamental plant, this one from Japan in 1825.  Unlike the previous two species, this is not spread by seed dispersal, but as a rhizome, where just 1cm of root in the soil can become a plant within 10 days.  It is a pernicious pest, and the roots cause damage to paths and walls, while the foliage shades out other vegetation.

The young stems are eaten in Japan, a sour taste similar to rhubarb, but also contains Emodin which has laxative qualities....

1 comment:

  1. we had japanese knotweed all over the Esk,but it was almost completely eradicated over the last two years due to a Pearl mussel grant from Europe!
    cheers G.F.