Spurge

This appears to be a euphorbia known as spurge. This is a large and popular family of colorful perennials that collectors covet. This plant is sen-evrgreen in warmer climates and want a place where it gets plenty of direct light depending on the cultivar. They are also known to have a bit of an unusual fragrance.
Some can grow as large as 4-5 ft. tall and wide. some are ground covers. A few re-seed politely and others are quite invasive as ground covers, so it is vital to understand which type you are choosing.
It is important to understand two things about this plant; 1) correct pruning. Prune only the canes that formerly had the old blooms on them all the way down at grown level when the blooms fade, but not so late that they set seed. 2) When cutting the canes, this plant will leak a milky white sap that can be a major skin irritant, in particular if you have any allergy to latex. Take care not to touch your eyes or face if you come into contact with this sap on your bare skin.