Northern Pearly Eye ~ Enodia anthedon (Lethe anthedon)
It's always fun to look for woodland butterfly species. Many woodland butterflies are medium to dark brown in color making them difficult to spot in shady places.
I photographed this Northern Pearly Eye at a local park, fluttering around under large oak trees by a creek. This seems to be their preferred habitat as their host plants include both shade tolerant and wetland marginal grass species.
Adults commonly occur in the upper midwest in late June through August. The caterpillars are light green with "prominent pink to red horns on head and last abdominal segment". (Caterpillars of Eastern North America)
One specific native host plant is Bottlebrush Grass (Elymus hystrix or Hystrix patula). This grass is a wonderful, shade tolerant grass.
It just started to flower, the long floral spikes look like bottle brushes and are extremely showy. The wide grass blades are blue-green in color. Bottlebrush Grass reaches heights of around 40" in average soils, taller in richer soils.
Bottlebrush Grass is browsed by deer (and dogs) so it's best planted where there isn't too much deer pressure.