I have them all over my yard up here in my little corner of the world. They came with the house. They are perennial and they self seed freely, although I'm pretty sure they do get some help from the squirrels. Since they self seed so easily, I would think they would be a good candidate for winter sowing. I am a beginner though, so you might want to get imput from someone with more experience WSing. They do survive our wicked winters here. I don't know much about your zone though. Good luck.

Yes, they can be winter sown, and will bloom on tiny plants in the 2nd year or regular size in the 3rd year.

Thanks! Just what i wanted to know.