Saponaria I believe.

Thanks, looks like you're right, image search shows fruit "capsules" of soapwort pretty much the same as my pic. I sure have alot of "------"worts on my lot.....

It can be vigorous.

https://www.gardeningknowhow.com/edible/herbs/soapwort/soapwort-plant.htm

I once saw some growing near a lake, thought it was pretty, so I dug and transplanted some to one of my shade gardens -- vigorous is an understatement. Once I realized that it wanted to take over the garden, I dug it out.... and continued to dig it out for years. :)

I loved the fragrant flowers but not the speed at which the plants spread. I removed it from my former garden.