This ground cover is sometimes given the name of 'fish plant' and will grow across a range of climates from temperate to tropical. It is native to South East Asia and China. The plain green leaf form is sold in Asian grocery stores and the aromatic strongly scented leaves make a great addition to soups or can be included as an ingredient when making Vietnamese rice paper rolls. In Vietnamese it is called rau diep ca. It spreads by underground runners and may become invasive but is easily controlled by yanking out the bits you don't want . The flowers are fairly insignificant white 'bracts' though the double flowering form 'Flore Pleno' is more impressive.
2017 update. I still grow this and can propagate on request.