I'm the resident lawn nut around the house, and the wife handles the flower beds and ornamentals (Hosta don't count, they are a life necessity and are treated as royalty).

So, her flower beds, her rules. She is prone to letting a "volunteer plant" go until it demonstrates any noxious or obnoxious behavior. This year there was a volunteer plant smack in the middle of the flower bed in front of the porch - so I watched it and prayed it wasn't a milkweed or something that would make a real mess when it flowered and seeded.

It finally flowered and I was able to ID it. A "Hardy Hibiscus" - 3' high, white Hibiscus-like flowers. I have never seen one (I only know the tropical Hibiscus), and there are none in the neighborhood.

Has anyone ever grown them, and how do they get the seed to travel believable distances?

We have had them before, but ultimately they turned out to be not so hardy, I guess. They didn't come back one year. We never had volunteers anywhere, so no idea how that happens.