Erysimum mutabile (wallflower)
This is one of my favourite hardy perennial wallflowers, with sweetly scented flowers that start off a creamy yellow and change to various shades of bronze and mauve, contrasting perfectly with the dark buds. A strong plant that forms a rounded shrubby perennial, 70-100cm in height and width in the right place. Prefers a reasonably sunny spot. 1 litre pot.