The 2011 Perennial Plant Association's pick for Perennial of the Year is Amsonia hubrichtii.
Better known (or at least commonly known) as Arkansas blue star, thread-leaf blue star or narrow-leaf blue star, this Arkansas native is hardy here in Zone 4.
Discovered in the early 1940s by a biologist named Leslie Hulbricht (hence its other common name, Hulbricht's blue star), this 36-incher can command a central place in the garden. The plant, somewhat similar to phlox, is topped by a 2- to 3-inch cluster of small, blue, star-shaped flowers. Narrow leaves about 3 inches long line each stalk and make the plant appear to dance in the breeze. Although its soft blue flowers appear in spring, its light green foliage keeps it looking good through the growing season. In fall, its wispy leaves turn a spectacular golden yellow.
Look for Amsonia in plant catalogs now and in garden centers this spring.