Master Gardener: What is this tree/bush/weed in my yard?

Q: I found this tree/bush/weed in my yard and allowed it to grow. It has now become much more tree-like, yet I cannot figure out what it is. I was hoping you could help.
A: The botanical name for your volunteer plant is Nicotiana glauca, commonly called Tree Tobacco. This South American native is well adapted to our mild Southern California environment and has become very invasive.
Tree Tobacco has a somewhat shrubby habit, but can grow to 20 feet tall and become more tree-like. It has bluish-gr