Ditto on Campanula rapunculoides (creeping bellflower). It's a INTENSIVELY invasive ornamental in my garden. I've been fighting it for years. It has false roots so when you pull it, it leaves tuberlike roots deeper which spread AND it also propagates from a thousand fine seeds. If you want to keep it in one spot Sass don't let it go to seed
Here's a link about it
http://www.invasiveplants.ab.c...
