I’m crazy for purple in the garden and right now the most outstanding shrub blooming its heart out is Yesterday, Today & Tomorrow. The blooms start out deep violet, turning to light violet, then white in 3 days. It’s evergreen and even lightly scented as well. The Monrovia brunfelsia magnifica gets 4′ x 4′, and is a slow grower.
One caution, however- it is toxic to dogs and cats, so plant accordingly.