Mirabilis jalapa or the Four O'clock Flower is an erect and bushy perennial with pointed, oval leaves and fragrant trumpet shaped flowers in red, yellow, white or pink.
The amazing thing about this plant is that you can get flowers of multiple colours on the one plant - and some are even individually multicoloured flowers.
The flowers open in the afternoon, hence the name.
They are good in borders or in pots or even as a dwarf hedge, but beware that they self-seed very easily and you'll find them all over your garden if you don't control them.
Relatively hardy but not to frost.