Tom I read David Pearman's article, thanks for the reference. His reference to articles (without citation) that determined knotweed 'does no discernible damage' is puzzling to me. This article I wrote in 2003, is a report to our local noxious weed board Observations on Knotweed infestation and dispersal events on the Nooksack River Mainstem - ........ http://flickr.com/photos/rchaard/… scroll to see the series of images Currently in 2011, this same site I studied has become completely involved with Japanese knotweed and replaced plants in normal ecological succession. Understory perennial plants and grasses have been displaced by knotweed in established forest since 2003. It is a hopeless irreversible situation. Our local fisheries official stated 'we are going to learn to live with this plant' ... Perhaps is different in Great Britain where natural is a different concept. I've been collecting seed from native plants since late 80's and I can document this displacement of natural stands of native plants by invasives. Responsible gardening is his message, but we do need to monitor those species offered for sale like loosestrife and others to assure they are not sold to naive customers. Rich H Bellingham, Washington