Dasylirion longissimum field specimen
There are actually two plants that you are looking at here. To see the whole picture you will need to scroll over. When the plant matures it develops a woody trunk, like a tree. You can see this is just beginning to happen on the bottom of this plant. Longissimum is both cold tolerant and fire proof. It is a non-invasive species that stays where you put it.

Dasylirion longissimum boxed
This plant has all the great features  everybody wants: Graceful shape. Fire proof. Drought and frost tolerant. Low maintenance. What more could you ask for! (It does not fruit $100 dollar bills, sorry) . Zones 14-24 (Sunset Western)