Salvia splendens, Scarlet Sage

Salvia splendens 'Van Houtii' has maroon coloured flowersSalvia spendens mixed colours of red ,pink and purple

Salvia splendens is a native of Brazil and has been grown for many years as a Summer bedding plant particularly the scarlet coloured 'Bonfire' variety.  Because it is frost tender it is usually treated as an annual but in warmer climates its shelf life can be extended by a couple of years. It becomes woody with age and is very attractive to snails as well as being prone to mildew so it is best replaced after that time. A light pruning with hedge shears seems to be the way to keep it looking good .If you cut into the old wood it often fails to regrow well . It makes a good understory shrub in semi shaded spots in the garden.
2017 update: The Van Houtii form is particularly good in semi shade and one I continue to grow.