Not sure, but I am in Michigan zone 6a and whatever that is, is rampant and wild around my house, including in my containers. They are not unnatractive and I let them be as long as they are not displacing something else I prefer...but definitely not exotic.
To me a weed is anything you don't want around. I like dandelions.Luckily I am semi-rural and none of my neighbors care about manicured lawns.
Any ideas???? I am completely stumped. They just appeared out of nowhere. I think it is a weed, but hubby seems to think he has some "exotic" plant growing!