What does well for you depends in part on your site conditions. And in Montana we have plenty of different kinds. Be advised that not much grows in very heavy shade, such as you might find beneath a spruce tree. Statice Sunflower Sweet Alyssum Sweet Pea Zinnia Very severe conditions, such as high salt and strong shade, are not conducive to growing much of anything. And remember, even though some of the above plants will tolerate dry conditions doesn't mean they are super plants and can go without water all season.
Water is especially important during the establishment period and under severe drought conditions.
It depends upon what kinds of shrubs you have. As a rule of thumb, we prune spring flower shrubs right after they bloom. These are shrubs that bloom with or before purple lilac. Remove the unproductive wood and spent flower clusters to make room for new growth. At the end of the season this growth will form flower buds that will open next year.