House-leek, or Hens and Chicks. This mat forming selection has 2-4″ rosettes of blue green foliage tipped with blood red edges. She holds her color well in summer heat, and produces a good supply of offsets. Again, grow Sempervivum in very lean soil where there is excellent drainage, such as at the top of retaining walls, or in rocky crevices. Yes, you can grow them in pots outdoors year round through zone 5, as long as the soil has good drainage.