In article ,
Malcolm wrote:

In the UK, Japanese knotweed is the ONLY vascular land plant that
has made itself an ecological or otherwise serious nuisance over
the majority of the country. And there are under a dozen that
are a serious nuisance in even a few parts of the UK. Out of
God alone knows how many thousand introductions.

I would add Rhododendron ponticum as an ecologically serious nuisance
over the majority of the country, with Heracleum mantegazzianum (giant
hogweed) perhaps the nastiest for humans.

Both are factually wrong, though such claims are made for both,
mostly by misinformation rags like the Daily Wail.

Rhododendron ponticum will not even establish itself in much
of the country, and is much less of a problem even where it is
invasive than many people claim. I have never seen more than a
patchy clump very far from the west coast, though there may be a
few more solid ones in places. Also, it isn't a major problem
(no more than, say, sycamore, ash etc.) where the woodland has
established a canopy (or even can do so?), as much of Cornwall
can witness.

The problems with Heracleum mantegazzianum are grossly overstated,
as the actual injury statistics show. I can't currently find a
link, but I previously saw one that made it clear that the
hysteria was almost entirely tabloid-driven. Yes, it can cause
serious harm, but so can lots of other things.


Regards,
Nick Maclaren.