You find it growing wild all over in the fields around here, from the birds dropping the seeds. What i did, was to put a stake by the plants, and in the spring i went out and dug up a bunch of plants moveing them into my patch. I planted them at about the same distance they were when i dug them up, and that was about a foot deep. They have done pretty well, considering i don't take care of the patch.
DM