With respect I disagree. It may be called invasive by one or two overzealous "scientists" but it doesn't mean that it really is. I live in BC but have never seen Centaurea cyanus here except in my own garden. I sowed it there some years ago and gradually it disappeared over a couple of years only, despite that I let it go to seed. So much for invasiveness based on my own observation and experience. And now to Wikipedia: "It is now endangered in its native habitat by agricultural intensification, particularly over-use of herbicides, destroying its habitat; in the United Kingdom it has declined from 264 sites to just 3 sites in the last 50 years. In reaction to this, the conservation charity Plantlife named it as one of 101 species it would actively work to bring 'Back from the Brink'. . . . The cornflower is considered a beneficial weed, and its edible flower can be used to add colour to salads. . . . It was the favorite flower of John F. Kennedy and was worn by his son, John F. Kennedy, Jr. at his wedding in tribute to his father." http://en.wikipedia.org/wiki/Cornflower
