It is an annual growing to a height of 150 cm (60 in), with spirally arranged leaves. The leaves are palmately compound, with five or seven leaflets, the leaflets up to 12 cm (5 in) long and 4 cm (2 in) broad and the leaf petiole up to 15 cm (6 in) long. The flowers are purple, pink, or white, with four petals and six long stamens. The fruit is a capsule up to 15 cm long and 3 mm (0.1 in) broad, containing several seeds. Flowering lasts from late spring to early fall.[1]

C. hassleriana is commonly cultivated in temperate regions as a half-hardy annual. Numerous cultivars have been selected for flower color and other attributes. The “Queen” series includes the cultivars ‘Violet Queen’, ‘Rose Queen’, and ‘White Queen’. The cultivar ‘Helen Campbell’ has gained the Royal Horticultural Society’s Award of Garden Merit.[3]

Plants in cultivation have at times been misidentified as Cleome arborea, C. pungens or C. spinosa.[2]

The Cleome Hassleriana Plant
Cleome hassleriana @ the back yard gardener
Cleome hassleriana @  M.Botanical Gardens