Sedum, commonly known as stonecrop, is a large genus
of flowering plants in the family Crassulaceae (Orpine family). It contains
around 400 species of leaf succulents that are found throughout the Northern
Hemisphere, varying from creeping herbs to shrubs. Sedums are hardy plants
with fleshy leaves, and have a wide range of textures, habits, and sizes.
Their star-shaped flower clusters are showy and often brightly colored. The
flowers usually have five petals, and there are typically twice as many
stamens as petals. While they do not take foot traffic, they are tough and
have low maintenance requirements. They spread and take root easily from
cuttings. Many thrive in full sun, but some like shade.
Sedums are well adapted to arid conditions because they use Crassulacean
Acid Metabolism (also known as CAM) photosynthesis, which is a carbon
fixation pathway present in some plants. CAM plants fix carbon dioxide (CO2)
during the night, and release it during the day, increasing the efficiency
of photosynthesis. The CAM pathway allows stomata to remain closed during
the day, reducing evapotranspiration (the transfer of moisture from leaves
to the atmosphere).
Because of their capacity to store water, survive drought, and grow in
shallow media, sedums are well adapted for use on extensive green roofs for
stormwater management and building insulation. The sedum-planted green roof