Our goal has been to use plants in our landscaping that are not only native to Montana, but native to the Missoula area. Once you consider the vast size and diversity of habitats in Montana, "Montana native" quickly loses meaning. what might be native to one part of the state, may not be native- or even appropriate to plant in another part of the state. Although exclusively using Missoula area plants may seem like a limitation, even in our small yard we have over 100 species of native plants. Nevertheless, trying to keep to Missoula area plants has been a fun challenge (the challenge being trying to keep my wife from planting species that don't belong) and goal.
Since we do not irrigate our landscaping, it is important to choose plants that are drought tolerant (hence using plants that are native to the valley), but we found that plants that would normally be associated with moist areas can thrive in the absence of water if you plant them in the shade, even partial shade. On the north and east side of our house and woodworking shop we have many species that you would normally find in riparian areas.
In our south facing front yard and boulevard, we have planted the most drought tolerant species. And in the backyard that does receive some shade (from the house, mainly), we have a greater diversity of micro-climates (the main two being being hot and dry and dry and shady). Click here for a list of most of the plants in our landscape, organized by location.