Oenothera can be annuals, biennials or perennials, upright or spreading in habit, with simple or lobed leaves and bowl-shaped, white, yellow or pink flowers over a long period in summer
O. fruticosa subsp. glauca is an herbaceous perennial to 80cm, with erect stems bearing smooth, ovate, glaucous leaves, reddish when young, and terminal racemes of light yellow flowers 3-5cm wide from late spring to late summer