This mat-forming perennial grows 4 to 10 inches tall and has white, 4-petaled flowers. It is native to the mountains of Europe. Rockcress is a spring bloomer that makes an excellent ground cover, and it works well in border edges and rock gardens. The fragrant flowers attract honey bees. Prefers lean, well-draining soils. Provide some afternoon shade if grown in USDA zones 7-8. Foliage can be cut back after blooming to encourage a denser growth habit.