One of the plants at the top of my favorite perennial list is Baptisia australis, False Indigo. Native to many of the states in the Midwest, it is reliably hardy and tolerant of most soils. It prefers full sun, but will also grow and bloom in partial shade as long as the soil is well drained.
In the garden, Baptisia reaches a height of 2-4 feet, and blooms in June. Use it in combination with ornamental grasses and peonies for a low maintenance, deer resistant planting. This perennial also works well as a shrub alternative in areas that get winter snowplow damage since it is cut back to the ground every year.
For flower arrangers, the tall, vertical flowers in June are a useful addition to the cutting garden. Add the color blue, in addition to purple, yellow, white and several muted blends of the many hybrids that are coming out now, to Baptisia's list of attributes. The foliage is a clean blue-green that can be used as a filler throughout the summer, and it has interesting seed pods for fall.
If you have the space, watch for some of the new varieties coming on the market this year... I'm excited to begin a new collection!