Celandine poppy

Celandine poppy, Stylophorum diphyllum, is a native woodlands perennial of the poppy family that is found in a few counties in Illinois, including Cook County, and is threatened by the invasive garlic mustard. It produces inch-long, hairy seed pods (below right) and small numbers of attractive, delicate yellow flowers throughout mid-summer.

It is said to colonize well and allegedly can be used as a ground cover. I tried introducing some in the hot, dry summer of 2012 in a spot that ends up bare in late summer after earlier bloomers die back, and it did well at the base of a tree in a relatively moist, shady area, and came back in 2013. I planted more in 2013 and 2014 in a shady, relatively moist area and they have thrived. The yellow blooms often arrive coincident and contrasting nicely with the blue of Virginia bluebells.