We call that wild mustard and I like it, too! I thik it can be invasive if left to it's own devices, but if kept in check and you're willing to pull a bunch of seedlings, I'd keep it!
I don't know the latin, but it's in the same family as broccoli and cauliflower. As a matter of fact, the first time I saw it in the wild, I thought some broccoli had escaped my garden! ;-) If I remember the latin, I'll let you know.
Wow, fast ID. Thanks Wingnut and others for your comments, I may have to move a few things and watch it close but it makes a beautiful clump. Do you know if it likes damp areas? I have one bed I would turn it loose in if it does. Nothing else is doing very well there yet except iris.
I really don't know how it'd do in a damp area. Here I've only seen it growing in dry places, but that's not to say that it won't grow in a damp one. Before you let it loose, though, do a little research on how invasive it can become in your area just to make sure. I don't think it'll be a problem for you as long as you keep a watchful eye out for seedlings that are where they aren't supposed to be ~ works for me here in Central Texas. But some things that are invasive everywhere else are the only things that can survive here! LOL! Like air potato ~ invasive other places but coughs and chokes here in August.