Sometimes known as "naked lady" because it is unaccompanied by foliage. The thick foliage grows in the spring, then dies back, leaving no trace that there might be a plant here. Then, in August, the flower stalks erupt suddenly and grow quickly. They are almost overwhelming in their subtle beauty. In the background is the Maryland state flower, the black-eyed susan. I had misidentified this species as Amaryllis belladonna, which looks very similar. See the comment below.