Very hardy, although not necessarily the longest lived shrub available. You can increase longevity by locating them out of direct wind (yes, they can suffer from that in winter) but even in an exposed location they will take a lot of abuse and can be rejuvenated through pruning. Just don't wait too long to prune - leggy specimens seldom regain their vigor or appearance after a hard prune. Well-drained soil in as much sun as possible and they will be happy.

I have a 'Brilliancy' in my rock garden/pond area that has been in for about 3 years and it is one of my favorite plantings there. As we speak, it is in full glorious bloom. It's in the 'Sunset' group with those dark magenta pink blooms and I like it so well, I added four more in different areas of my landscape. I also have some 'skanbergii' which I am much less fond of but I would highly recommend the 'Brilliancy' for both the bloom and the structure of the plant.

Expect trouble from many below about 15 degrees F. Seattle Arboretum rockrose collection was hammered in 1990. As with hebe, there are more hardy standouts among them--like the common white Cistus x hybridus that is even used in mall and park plantings--that hold up when many others fail. Ceanothus, Cistus, Escallonia, Hebe...on the whole heat lovers for good drainage in sunny positions, that can be expected to need replacement after hard winters. The vivid yellow green or grayish foliage many of them have are indicators of plants that like it warm.

A planting design sidenote is that the vivid yellow-green ones and the grayish ones clash visually, so it is a good idea to use either one group or the other in proximity but not both.