How can a shade-loving, moisture seeking plant like bugbane be native to Arizona? It's native to just a few places - deep canyons in the Arizona dessert where it's protected from the sun and picks up moisture from small rivulets and streams. In the garden, it's a strong vertical accent in the shade border, and with its creeping rhizomes forms a good-sized clump in a year or two.

There are over 25 different species of bugbane or Actaea,
spanning Europe, Asia, and North America. They're generally woodland
plants, happiest in dappled shade and cool, consistently moist soil.
Most form mounds of toothed leaves and then in mid-summer send up spikes
of tightly packed flowers, often followed by conspicuous berries. NOTE:
Berries are poisonous to people and rabbits; harmless to birds and
butterflies.