Sedum spurium 'Schorbuser Blut' (Dragon's blood)
This German introduction is promoted as one of the best groundcover for all sorts of impossible situations. While it won't grow in deep shade, it tolerates semi-shade and grows in almost any soil. It is an easy to grow evergreen sedum that has green leaves and red flowers in the summer. In the autumn the leaves turn maroon and persist through much of the winter.
The stem is ropy and roots freely. In most areas, only the leaves near the ends of the stems are truly evergreen. It can be given a trim in spring to encourage branching. I think it is best grown in our cold Peak District climate in full sun and very well draining soil. Ht 10cm S 30cm.