Silphium perfoliatum

 
One of the best cold-hardy perennial plants for wildlife is the bold and stately Silphium perfoliatum. In the late summer to early autumn seasons, 2-3" yellow flowers are borne a top its 6-8'(10') square stems providing nectar and pollen for a variety of insects. When the flower heads mature, birds, especially goldfinches, descend upon the plants to devour the ripe seeds.
The large, up to 12" long, leaves provide additional benefits for wildlife. The leaves clasp around the stems forming water basins or "cups" which collect moisture. These moisture-filled cups provide birds and insects with a source of water. The ample-sized leaves also provide wildlife with shelter.