Orostachys are a group of rosette forming plants consisting of thirteen species in the genus. Some species have two types of leaves forming a taller outer ring
on each rosette, encircling a short spiraled center.
In other types, they resemble an odd looking Sempervivum and you would be excused for not realizing that they're a completely different genus.
They are also similar to Sempervivum and Jovibarba in that they are monocarpic; they will form an interesting cone shaped flower stalk which explains the common name of 'dunces cap' after which the main rosette will die, hopefully leaving behind a ring of smaller 'chicks' to take its place.
One species, Orostachys spinosa originating in Siberia and Mongolia, is reported to be the most cold tolerant of all plants that have Crassulacean Acid Metabolism systems. They can survive down to -40 degrees Celsius, and can even photosynthesize under snow cover.
If you’re lucky enough to be able to find one of these gems for your garden, here are a few tips on successfully growing these rare hardy succulents;
I'm always on the look out for more species of this unusual and interesting genus. I don't mind growing them from seed, or welcoming a tiny offset or chick into the collection.
Orostachys minuta - a bright green version of Orostachys spinosa, but much smaller. The biggest rosette in this picture is only about 2.5cm (1") across (the size of a quarter).
I'm also hoping to get some seed of Orostachys thyrsiflora - the most evil looking of the Orostachys tribe, with long and pointed outer leaves, guarding the inner center, with its spikey foliage.
As I find out more about these weird looking and challenging plants, the more I am fascinated by them. I'm looking forward to some success with growing them in my xeric gardens.
See this page for more fascinating information about Orostachys pollination.