Aubrieta deltoidea is a species of flowering plant in the mustard family. Common names include lilacbush, purple rock cress and rainbow rock cress. Zone 4a to 9b. It is native to southeastern Europe, but is grown worldwide as an ornamental plant and it grows wild in some areas as a garden escapee. This is a small herbaceous perennial forming carpets of green spoon-shaped to oval-shaped leaves, some of which are lobed. The showy inflorescence bears small flowers with four lavender to deep pink petals. The fruit is an inflated, hairy silique up to two centimeters long.