Further to the Facebook convo - I cut down my verbascum the second the last petal drops. If you're not going to do that, don't grow it. And don't give out seeds to anyone.

I have never known wild columbines to take over... I always have one or two here & there but not lots. I do have some domestic columbines that seed ALL OVER my flower gardens though! They are even in the grass.

I find love-in-a-mist (Nigella damascena)really seedy. I always have tons of it and just pull it where I don't want it. Annual poppies are the same, except unlike Nigella it doesn't seem that their seeds will lie dormant for more than one year, so if you deadhead them all, you won't have any the next year.

One thing that is barely controllable in my garden is Star-flowered False Solomon's Seal (Smilacena stellata). It really spreads to fill a shady area and has tough stems and running roots, and Round Up doesn't kill it. I do like it but I'm scaling it back a lot this year.

Oh gosh and never plant Siberian Motherwort. It's seedy too, and fairly unattractive.

Gil, that's odd about the columbines. My domestic ones rarely self-seed and i wouldn't mind if they did! (not too badly, of course!).

Yes, i forgot about poppies. I tend to find them in odd places too. I've taken the pods and shaken seeds along the road but none have ever come up there.

I like nigella but that's another thing that i don't have a lot of luck with - probably because i don't have a lot of space for annuals and end up putting it in a corner somewhere or in a container. You're right about the seeds, though - my cousin sent me some seeds once and i lost them. Four years later, some nigella sprouted!

People complain about lily-of-the-valley. Mine has taken years to establish itself, but is starting now. I might be cursing it too someday! LOL