Can you please help to identify this invasive plant?

Question

I have a plant that is spreading to all corners of my yard, it grows up to 6 feet tall, has small purple flowers, and doesn’t seem to look like Campenula. It has a white sap that causes itchy hives so trying to cut it back or get rid of it requires full protection. It won’t die. We’ve tried round up, we’ve tried digging it out 2 feet down, we’ve thought we got all the rhizomes, but it keeps coming back and it spreads to a new area of the yard each year. No one can seem to tell me what it is. Can you please tell me what this is and how I can get rid of it for good? Pictures attached.

Thank you!

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Answer 1

It could be Showy Milkweed. It is considered a noxious weed in some areas. Do you see lots of monarchs? It is a host plant for the monarch caterpillar. As such, our articles are about growing milkweed, not getting rid of it. You may want to keep a small patch contained for the butterflies. To eliminate it, a product containing glyphosate should take care of it.

There also is creeping bellflower in Canada, but it usually grows only to 1 meter (3 feet).

https://cwf-fcf.org/en/resources/encyclopedias/native-plant-encyclopedia/?plantid=694