In article ,
Martin Brown wrote:
On 29/08/2014 14:16, stuart noble wrote:
On 29/08/2014 11:28, Tom Gardner wrote:
Swansea University scientists trial knotweed killers

Swansea University scientists are conducting the largest field trial in
Europe to find new ways of killing Japanese knotweed.

Introducing the specific Japanese parasite of knotweed and hoping that
it doesn't do a cane toad on us would be one way.

They are checking that out very carefully.

The plant is one of the most damaging species in the UK and costs £8m a
year to bring it under control in Wales.

Carwyn Jones has been finding out more.

http://www.bbc.co.uk/news/uk-wales-28975734

Where I've seen it on public land the problem appears to be that the
authorities can't adopt a little and often strategy. They prefer the
annual blitz, which appears to be the least successful method.

Whenever this comes up I am reminded that in my youth we played in a
garden of the local "big house" which then in addition to a dangerous
limestone grotto had fairly rampant Japanese knotweed growing as an
ornamental. It would expand to fill the available space but from memory
it could not compete with horsechestnut trees or rhodedenrons at all.

Even the local brand of rose bay willow herb could out compete it on the
margins. It makes me wonder if there is some super strain that got
completely out of hand and has become the scary plant of tabloid
headlines or is it all hysterical hyperbole.

It isn't ALL hysterical hyperbole. Japanese knotweed needs ample
water and light, and will eliminate all other plants from damp,
open locations. However, under shade and in drier conditions,
it will do no more than survive. The reason that it's said to
be Public Enemy Number One is that such locations are restricted,
and there are a lot of other plants that need the same conditions
that are already threatened by habitat loss.

Amusingly enough, buddleia will do the same in extremely well-
drained locations (e.g. old walls), but there is no 'native' plant
adapted to solely that habitat. Indeed, it often invades in
locations where no other plant will establish itself! So that's
not an ecological problem (in the UK), though it's a pain in the
neck for Network Rail ....


Regards,
Nick Maclaren.