S. ‘Essue’ is a hybrid created by Gary Hunter, and remains one of my all-time favorites. Its rich purplish blue colour, yellow throat and dramatic markings make it one of the most beautiful of the Streptocarpus cultivars, and it is also vigorous and easy to grow. I grew this plant under fairly bright artificial light, in a well-drained medium. I have personally found that most of the rosette-type hybrid Streps do well if allowed to get dry enough that the tips of the leaves start to wilt, although that may be risky unless you are watching them closely.
A more recent photo, perhaps more accurately representing the color, can be seen here.