Greater Blue Lobelia is WONDERFUL! It blooms late, likes damp areas and self seeds. I have a ton of it now, after having been given one plant several years ago. It took a while to establish. It does not grow in my sunnnnnny sandy dry area but self seeds in my damp area. Currently inbetween my newly planted blueberry bushes (acid soil).
I am going to dig and transplant many plants to an estate that I am working on in the spring where they have an old quarry and the water runs down when we have rains and collects against another boulder before moving on. Hope that will be a good site for it.