Oenothera fruticosa is a perennial herb to 1 m tall, stems slender, appressed-hairy, colonial from rhizomes.
Leaves alternate, stalk 0-1 cm long, blade to 11 cm long, 2.5 cm wide, elliptic; leaves of first year rosette egg-shaped.
Flowers clear, bright yellow, showy, to 5 cm wide, 4 petals, 1.5-2.5 cm long, notched at top, folding up at night; calyx lobes 0.8-1.8 cm long, calyx tube 0.5-1.5 cm long, obligate outcrosser.
Fruit dry, capsule, sharply 4-sided, club-shaped, 0.4-1 cm long, 0.3-0.4 cm wide (Radford et al. 1968).
Wetland status: FAC.
Frequency in NYC: Very infrequent.
Habitat: Open woods, fields, disturbed sites.