Hi Ron,

This is an invasive plant called creeping bellflower. It's pretty when blooming, but will take over a garden. It is very hard to eradicate.

First off, cut off all the flowers and do not let the plant go to seed. 

Digging works to remove plants but you must dig deep. The plant fools you because you think you've gotten all the roots if you dig a few inches down, missing thin white roots that connect to a bigger root system a foot down. They look like carrots.

Herbicides, applied properly and repeatedly, will kill the plant. Timing and other advice are on the sites below:

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

https://northerngardener.org/creeping-bellflower/

https://cdn.shopify.com/s/files/1/0145/8808/4272/files/A3924-05.pdf

Good luck.