The Hoshovsky paper goes on to elaborate on competing with native flora in the "Impact" section. The opinion on shade tolerence is sourced in that paper from a paper by J. P. Grime from Nature written about shade tolerance in several species. The abstracts of the Heisy papers are more concerned with using the allelopathic chemicals as herbicides and thus they do not discuss the interaction with other plants in an ecosystem at lenght, though it is certainly mentioned. It's ability to supress competiton is mentioned in probably half the sources, including the Hoshovsky paper, which sources its information from a paper by F. Mergen from the Botanical Gazette. The NPS is already sourced as claiming it to be a serious weed. I feel that everything is sourced strongly enough as it is (though I will get back to you on Australia, New Zealand and Europe), and that edits of this sort ignore that fact, but nonetheless I will work on your suggestions. Thanks very much for your input.  | talk  |  contribs