Crassula alstonii  Crassula alstonii is a species of succulent in the genus "Crassula" found in Cape Provinces, South Africa.The species is in USDA hardiness zone 10a-11. Like some other plants of the genus, "Crassula alstonii" is easy to grow and needs below average to average water. They need light shade and need 6.1-7.8pH soil. They can be easily propagated from a single leaf, along with offsets.