Have a look at these 2 photos of our sedum field which were taken from about the same vantage point. The first one was in spring when the sedum is in full bloom and the second , in winter, about this time of year. You can see how different the field looks when dormant over winter and subsequently so fabulous in spring. Your roof too, will change with the season and thus give you an altering view depending on the time of year. Never fear that things have gone wrong with your sedum in winter as it will just be sleeping and preparing for the spring show!