Asked April 15, 2021, 7:21 AM EDT
Boulder County Colorado
Shrubs which need no water and have no sun exposure are fairly limited. However, there are some that may work for your location. But it is important to note that any shrub, including the hardiest of natives, will need some water the first couple of years to become established. And, to insure that you don't lose a plant during a very droughty period (summer or winter), some supplemental water may be needed beyond the first couple of years.
I would suggest considering some of the native plants that are shade tolerant as your best bet for success. With no sun at all, this will be a bit of an experiment...and you may find that your shrubs are leggier and less full than pictures that you see on the web or in books. Nonetheless, here are a few shrubs that have the best chance:
Natives: Mahonia aquifolium (Oregon grape holly); Ribes aureum (golden currant), Amelanchier spp.(Serviceberry), Rubus deliciosus (Boulder raspberry); Aronia melanocarpa (black chokeberry)[note: not native to this area--native to eastern N. America], Amelanchier spp. (serviceberry).
While getting these established, there are a number of shade and drought tolerant ground covers you could also plant to fill in.
Here are several references you might look through to see if anything else catches your eye:
https://extension.colostate.edu/topic-areas/yard-garden/native-shrubs-for-colorado-landscapes-7-422/ (note: only plants that indicate they are shade tolerant should be considered for your area)
Best of luck!