Big mountain sagebrush is (or was) one of the foundational species on our rangelands prior to European occupation. But it's poor forage for cattle, so one of the first activities a new rancher would undertake was to rip out or burn existing sagebrush and replace it with non-native grasses. There are a few pockets left in the Missoula valley, and more substantial ones down the Bitterroot. 
 
Big basin sage provides crucial habitat for many grassland birds, and serves as a 'nurse plant' for seedlings of native forbs and grasses. The incredibly extensive roots find moisture even in the driest months, although they can tolerate periodic deep irrigation. And as a bonus: the deer seem to avoid this one! 
 
The shrub itself is gorgeous, with dark twisting stems and bright silver foliage.  It tops out around 6 feet, and goes especially well with rubber rabbitbrush. Plant in any dry sunny spot where you want no-hassle shrubs. Goes great with bunchgrasses, especially prairie junegrass, idaho fescue, and bluebunch wheatgrass.