We grow the majority of our perennial shrubby wallflowers in our dry garden. Full sun and a free draining soil is preferred. Most have tidy, narrow, small leaves, forming a low to medium, shrubby framework of stems. Flower colour stretches across the whole range, with some forms having 2 or 3 differing coloured flowers on the same spike! Don't be afraid to trim lightly after flowering, or even once peak flowering is over. This will help maintain the shape of the plant and maybe produce a later second flush of flowers. These wallflowers are part of the Brassicaceae family, including the familiar edibles of mustard, cabbage, broccoli etc and all produce flowers with four petals, arranged in a cross shape, hence the old family name of Cruciferae.