Be sure to check with your city or town, and with the power company, for any ordinances prohibiting plantings within a certain perimeter of the power lines. If you get the go-ahead, then the following small trees would be okay for most areas in Montana.
Russian olive can become a weed if planted on sites with moderate to good growing conditions.
So if you have a pretty good site, choose on of the other small trees for planting. As with all fruit and vegetables, the ultimate size of the crop is very much dependent upon proper watering at the right time. There are several important stages in watering potato plants that correspond to growth phases of the plant. After emergence soil water shortages slow root development and plant growth by interfering with nutrient uptake. Supply plenty of water at this time, but not too much.