Eryngium. Not invasive in my experience in our region, but can be pushy in the garden. "Doesn't like to share with others". Not easy to remove once it's in there, but no, not invasive. But then again, my Linnaria self-sowed and was pretty in Seattle and is downright annoying here in the Chehalis valley. My book (Sunset Western Garden Guide--gotta have it) says to sow in place. I have never planted this plant, only maintained it. Very beautiful. Also, apparently sensitive to winter wetness and slugs, so sow them in a well drained, sunny location. Not a thistle relative. Carrot family, Apiaceae, apparently.
Thanks ! I have a WGB also, but am being lazy today (Ha !not ever going to happen !)
Yes Linnaria will self sow.....we have enough of that going on with tomitillos and Nasty-stutiams !!!!!!!
TOOK OVER the garden !