On further thought, and after poking around the database a bit, perhaps it would be useful to add a check box of "May be invasive - please check your regional USDA website, review the comments section, and plant responsibly," or something along those lines. That would perhaps spark more comments about how invasive a plant is in different regions without the "OMG, do not plant this, it should be banned from the planet" tirades. I rather find those unhelpful, particularly when I know a plant is better behaved in my locale.
(The "May" could be emphasized, perhaps with an underline or bold.)