Grows well in CA, heat and cold are not a problem - however slugs and snails seem to like the Orostachys that lack pointy leaves.
In winter when exposed to frost the outer leaves will die and the core of the rosette will curl into a tight ball and stay that way until opening up in spring. They look pretty ratty compared to semperviviums in winter, but don't get burned to the ground like sedums. This species grows best in cool weather and appears dormant mid-summer, it grows all winter long when protected from frost in a greenhouse, even with lows in the 20's. Frost appears to trigger them to curl up and go dormant.
Orostachys iwarenge produces large numbers of offsets on stolons that are about 3" long, so despite the plant's small size it should be placed in a bowl or trough that is at least 6" in diameter so the offsets can root. I tried them in 3.5" pots and the offsets all hung over the sides and failed to root. Excessive heat or cold will cause the stolons to wither, leaving the offsets to fend for themselves.
Orostachys are monocarpic (a rosette dies in flowering), so it is important to keep plants and offsets of different ages to avoid losing them to flowering.