Wouldn't the problem be knowing if it was truly a native plant as opposed to an imported plant that has successfully transitioned to a new geographic area? I'm thinking 'Johnson Grass' and 'Kudzu' and, I think, Bermuda grass as well. In some areas they have become so ubiquitous that I wonder if most people realize they aren't considered native plants. Distinguishing between an indigenous plant and an introduced plant might be difficult.
Of course, for those really successful interlopers they might as well be considered native at some point. They aren't going to go away.
I do like to know the origins of plants, though. That provides a lot of knowledge about what a plant may require to thrive.
