You won't be able to have just one. The hybridizers have gone nuts. Available in colors that can be dizzying, with patterns to match, many varieties have been bred that perform better in the sun, than in the presumed shady location.
Heights vary from the downright petite, to the potentially monstrous.
L ose your boring Marigolds, and Petunias. No occupation is so delightful to me as the culture of the earth.