Datura inoxia, Datura wrightii, or Brugmansia. I haven't found them to be
"very
"xeric" and are very heavy feeders.

There is a big difference between Datura and Brugmansia. Datura grows wild here
in Colorado out on the plains with no supplemental water or fertilization. It
is a feature in the xeriscape prairie garden at Denver Botanical Gardens where
it also receives no supplemental water or feeding and seems to thrive, even in
our drought.
sed5555