Are all yellow irises invasive?

What is this about yellow irises being invasive? Is it all yellow irises? I have some that have kept growing despite my black thumb, so I suspect they may be invasive. What is it about them that make them invasive? It won�t break my heart to get rid of them if they are invasive, but I would like to leave them otherwise because they do survive my neglect. Thank you.

Don't waste your yellow iris just yet. What you have is probably not native but not all yellow iris are invasive. Please post a photo of your plant. I know it won't be in bloom but there is a slim possibility that somebody might be able to tell it apart from the natives. The one that is highly invasive is Iris pseudacorusis. That forms thickets much like Narrow Leaf Cattails do. One of the big problems with it is that it has an incredibly high nitrogen requirement. Not good for native species.

I will try to get a pic uploaded. It does spread vigorously but I've never had it in one place long enough to see if it resembled a thicket.

I searched for a picture of pseudacorusis. That's definitely not my yellow iris.