Stylophorum diphyllum (Celandine Poppy)

Native wildflower whose showy yellow blooms appear in very early spring.  Plants grow to a height of 1'-1.5' with a spread of 9"-12" and naturalize readily.  Prefers part shade to full shade in medium to wet soil.  Plants go dormant in the summer and should be paired with later-blooming perennials that will cover the gaps they leave in the garden.