This African is one of my favourite salvias because of its smooth grey evergreen foliage and large pinky mauve flowers in winter/spring. After the flowers drop the calyx goes a deep pink. Once I saw it hedged into a rectangle shape which was stunning.
It is an easy plant to grow unless it is tropically humid, it is tolerant to frost and drought.
I think 1.5m would be an average height. The plant suckers mildly around the main stem and these can be dug up for propagating. Cuttings are slow to grow under home conditions but it sets some seed which is probably easier.
limit of one only