Sedums have a long established reputation, but there are a huge variety of other alpine plants that can do a similar job whilst providing a lot more visual interest.
Succulents should be used in drier areas where you have limited depth and want to minimise irrigation. These are not as suitable for areas with high regular rainfall.
Dwarf alpine bulbs – need at least 100mm depth. This is one of the new key areas of research in green roofing and we think it will become more common practice, as an economical way to bring more aesthetic and ecological interest to roof planting. Add for splashes of colour while your other plants are establishing.
Wild Herbs – fit well with all planting schemes, but can be more accustomed to temperate climates. Leave much longer lead times for Alliums unless you are confident of buying autumn bulbs and planting them direct to the substrate.