During my talks I make the suggestion that although there are justifiably invasive unwanted species in our part of the world, there are many “black-listed” plants in my view that we may in the future thank our generation for having introduced due to their being valuable and healthy edibles (the positive impacts of such plants haven’t as far as I know been included in the total evaluation of black listed plants.  There are other positive factors such as Fallopia japonica (Japanese knotweed) being an important bee plant as it is late flowering and also a cultivated source of medicinal resveratrol  (an antioxidant also found in red wine and peanuts).  In my book Around the World in 80 plants, there are about 7 species categorized as having “severe impact” (SE) on the Norwegian Black List, 2 with “high impact” (HI) and at least 6 with “potential high impact” (PH).  At least two others in the book (Dandelion and Ground Elder) are often referred to as invasive, but as they are well established and introduced before 1800 are not on the black list!  As they say  “If you can’t beat them, eat them…” and I might (jokingly) add “If you can’t eat them, beat them”….  ;-)

The link is a recent one arguing against the hysteria by a US based ecologist pointing out that “our panic about invasive species might be a major mistake”
http://www.cbc.ca/news/technology/battling-invasive-species-can-be-a-mistake-ecologist-says-1.2861822