An extremely variable woody perennial 30-70 cm tall and often grown as a biennial or annual. Leaves lanceolate to narrow-lanceolate. Flowers mostly yellow to orange-brown, fragrant, late spring in cool areas, winter in warm areas. However, there may also be reddish and purple tonings. [Cheiranthus cheiri L.]
Bedding plant selections of various colours available, often double. Many of these are of hybrid origin and their precise parentage is unclear.
E. ×allionii Hort, Siberian Wallflower, is occasionally grown as a biennial; it is smaller and more compact than the English Wallflower with basal leaves less than 2 cm wide and the colour range of cultivars is restricted to deep yellows and oranges.
E. mutabile (Spreng.) Boiss. & Heldr., also with basal leaves less than 2 cm wide, is sometimes listed with cultivars and a variegated leaf form but distinctions between this and other species are unclear. It is sometimes placed in synonymy under E. bicolor.
Source: (1997). Brassicaceae. In: . Horticultural Flora of South-eastern Australia. Volume 2. Flowering plants. Dicotyledons. Part 1. The identification of garden and cultivated plants. University of New South Wales Press.