This is called an annual salvia, but it will also often survive through winter. In any case, it also self-seeds so you will never be without it! It has dainty flowers of red, pink or white and forms a pretty, hazy effect, from late spring to winter. It is a good filler plant and will grow in sun or part shade.
It is a rather brittle plant which grows to about 50 to 80cm tall , but I have seen taller variants that grow up to 1.5 m in height and have quite a presence, mingling effectively with Dahlia, Pentas and other long-flowering plants. Regular deadheading will prolong the floral display. If it survives winter, prune it hard at the end of that season and, hopefully, it will regrow.