In article , Nick Maclaren
writes

It would be extremely interesting to see a botanical/horticultural book
on weed issues in the UK, describing the circumstances under which
particular species are likely to be a pest. There is a lot more to
this topic than most people realise.

There was a mini-thread in urg a few years ago on what 'weeds' people
had most trouble with. It's not just native species, of course, it's
also the invasive introductions (himalayan balsam, japanese knowtweed,
Rhododendron ponticum) and even the more robust garden plants - Sacha
has laid herself open to us N gardeners by expressing a desire for
Alchemilla mollis. And od other gardens uproot wholesale aquilegia and
Malva moschata?
--
Kay Easton

Edward's earthworm page:
http://www.scarboro.demon.co.uk/edward/index.htm