In article ,
Stewart Robert Hinsley writes:
| In message , "David
| (Normandy)" writes
|
| I think you may be right - Hemp Agrimony (eupatorium cannabinum). I've just
| Googled for images and while mine aren't in flower yet the foliage looks
| right. Google says it is a wildflower attractive to butterflies and can even
| be bought from a number of plant nurseries, which would perhaps imply it
| isn't a pernicious weed?
|
| There's a clump 3 or 4 miles down the canal. As British wild flowers go
| it's one of the bulkier ones. Stace says that it grows to 1.5m, and I
| observe it to form considerable clumps - I guess that is spreads by
| rhizomes. (Not as bad as the 20 yard clump of goldenrod that's colonised
| one roadside verge.)

We walked along some canal near Diggle, and there was a lot of
Himalayan balsam. I ranted to my wife that most of the claims of
the perniciousness of weeds in the UK are tripe - there are a FEW
that are seriously invasive, like Japanese knotweed, but most, like
buddleia, balsam and goldenrod, don't eliminate all other plants even
where they become established. They may become obtrusive, or even
dominant, but that isn't the same.

Excluding the few Arctic remnants, which will probably be wiped out
of the UK within a century by climate change, essentially all of our
flora and fauna are recent invaders, almost all of our ecologies are
artificial and all of our endemic species are recent offshoots from
ones that exist elsewhere. We are probably the country-sized area in
the world that needs to worry LEAST about alien species!

So what plant species are a major problem, in the sense of seriously
threatening to eliminate existing species or all examples of particular
ecologies? I have been told that Rhododendron ponticum is in a few
places, Japanese knotweed definitely is, some waterweeds are reported
to be, but what else?


Regards,
Nick Maclaren.