What perennials attract butterflies?

A short list of perennials that will attract butterflies includes Yarrow, Coneflowers, Blazing Star, Asters, Milkweed, Butterfly weed, Black-eyed Susan and Bee balm aka Monarda. These are all hardy to Minnesota. Check here to see more butterfly freindly plants found at Gertens. 

Butterfly bush, which has lovely big flowers, is highly attractive to butterflies. However, it is primarily a zone 5 plant; the Twin Cities is mostly zone 4 with the exception of south Minneapolis, which is zone 5 due to a “heat island”.