This plant popped up in my yard in early June. I'm located in San Diego California. It just started growing out of the mulch with no watering or anything. It looks like a fast growing annual to me. But it's grown remarkably well with no help and I'd like to plant it purposefully next year. It is just now growing some buds or seed pods and looks like it might flower. I'm hoping that I can get some seeds from it...what is it?