this is a basil plant that grew in a tomato sauce can this year. later in the summer, i set the can in some soil in my in-law's tomato garden, so it would get watered while we were away. at the end of the summer, i picked up the can. i should not have been surprised to see that it had sent roots out through the bottom of the can.
rooting is so natural for plants. even people can't help rooting, if they stay in a place for a while.