I recently bought a Helianthemum ‘Ben More' (AKA Rock Rose or Sun
Rose) & have potted it in coarse organic compost. It gets about 3½
hrs/day direct sunlight + several hours good level of ambient light.
Most of the leaves seem to have died off, although there are one or
two new ones appearing. There were several quite severe frosts a few
weeks ago. Any suggestions what I might have done wrong?

TIA, Jeff