This is a large and varied genus, but most members are grown for their foliage and have insignificant flowers. Several species have medicinal or culinary uses and many have fragrant leaves.
There are nearly 350 species, made up of evergreen and deciduous shrubs and herbaceous perennials, mainly from the temperate regions of the northern hemisphere.
These plants thrive best in full sun and nutrient-poor, free-draining soil. As such, they are ideal in a gravel garden.