i use to have a fence line separating an alley from my back yard. i put them along the whole fence line. once they were in full bloom, they were beautifull an the cline to everything they spread like crazy too
The only thing bad about them is if you don't collect most of the seeds or pull up most of the plants that come up the next spring they can get out of hand quickly. Other than that, they are really easy to grow and produce a lot of beautiful flowers.