Cardoon- how invasive are they?

[Tracydr]

I started some cardoons, wanting to try them because I had such success with artichokes last spring. I didn't realize they were an invasive. Before I make a big mistake and plant them in the ground I thought I'd ask just how invasive exactly are they?
I'm planning to plant a bunch of artichokes and thought I would do a couple of cardoons, but I'll toss them if they're really bad.