Hi,

This is creeping bellflower, a weed that’s extremely hard to eradicate. It will quickly take over.

Digging works, if you get the entire root. The plant fools you because once you remove the carrot-like white roots six or seven inches down you think you've got the whole thing. You don't -- the root near the surface is often connected by a thin white strand to a large parent root deeper down. Any small piece of root left behind will result in a new plant.

Spring is a good time to try to dig the plants out. Dig out as much as you can. Then watch for resprouting and baby plants and immediately spray the leaves with glyphosate (the most common brand of this herbicide is Roundup). While creeping bellflower is resistant to many kinds of herbicides, the youngest and smallest plants seem susceptible to glyphosate.

Chemical treatment is most effective now and in the fall. With glyphosate you should spray, wait (the plants often don't show damage right away) and if after a couple of weeks the plants still look strong, spray again. Be careful; read the label before using. Glyphosate should be applied only to the plant you want to eliminate, it will kill any green plant.

Here's more information from the U and from a master gardener.

https://extension.umn.edu/weeds/creeping-bellflower

https://www.ramseymastergardeners.org/post/creeping-bellflower

I hope this helps. Good luck!

Hah! Good luck!