Wild blue phlox, Phlox  divaricata
 
Up to 50 cm tall. Pale blue, fragrant flowers bloom from April to June. Also known as wild sweet William. Often found in dense deciduous woods. Great ground cover.
 
Ecology:
Important source of early-season nectar for swallowtail butterflies, hummingbirds, and other pollinators. Larval host plant to 8 species.
 
Growing condition:
Part sun, rich woodland soil.