In theory, yes - in practice, they often survive the winter, even if they are cut to the ground by cold weather, and may have seeded themselves.

Yes in our neck of the woods - annuals!

In my garden they are perennials, but could be new plants seeded by the original. I actually pull loads out as I find them quite invasive. (I think the birds keep dropping seeds and they come up all over the place.)

Nope Sheila the plants themselves do a good job or propagating themselves... You may think of them as a perennial but I bet they are actually growing annually from seed.

Ah, you're probably right Moongrower. That would explain why they always seems to be in the same place as the previous ones. I don't mind them, but I don't want a garden full of them!

I do get some that survive into the next year, MG. I'm always delighted to see them, too!