White goatsbeard

White goatsbeard, or sometimes just goatsbeard, Aruncus dioicus, a wide-ranging woodland perennial native to North America, shown here with its astilbe-like brushes just starting to bloom.
 
For more about Goatsbeard and native plants for the Midwest, especially those that do well in shade/moist areas, see the "book" on this website, Gardening with Native Plants in Shady Evanston.