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Q.Don’t Promote Himalayan Balsam!

I found a reference to Balsam in your list of best self-seeding plants. They are hugely invasive and have colonised large areas of the British countryside. They are trying to eradicate them but once they have spread it's really difficult. People are starting to look at Balsam in the same way that they look at Japanese knotweed. Volunteers all over the country going out to try to rescue clogged-up river banks and other areas, but it's an uphill struggle. I can't imagine that the US would be immune. Please don't suggest that people grow them!