Perennial with bladelike leaves growing from yellowish-orange rhizomes. Flowers in terminal cymes at ends of branches, 1½ to 2½ inches across. Sepals and petals (together called tepals) similar, spreading, orange, with crimson or brownish spots. Each flower remains open for only a single day. There are 3 stamens. Blooms July–August. Leaves in flattened fans, nearly identical to those of the German garden iris, long and broad. Fruit a pear-shaped capsule about an inch long, that splits open and withers, revealing shiny black seeds, looking very much like a blackberry. The seeds remain attached for many weeks.
Similar species: At a glance, blooming blackberry lilies may be confused with day lilies (Hemerocallis), which have also escaped from cultivation. Day lilies more often occur in dense colonies in grassy areas, and less in dry, rocky areas, and although their leaves are creased somewhat, they are not folded into flattened, swordlike fans like those of this and other irises.