This plant is a succulent with a stem full of thorns. It is unusual in that most succulents do not have leaves.
It can grow 2′-4′ tall, given full sun. It will remain in bloom almost year round, given sufficient sun.
It is very cold sensitive, so keep it away from drafty locations.
This plant is part of the poinsettia and castor bean plant family ( Spurge ). It is a succulent and so likes full sun and very little water. Water only when the top inch of soil it dry to the touch. But don’t let it fully dry out.
The milky juice inside the stems can cause a skin rash.
You can gently bend the stems when they are young and grow them into a sphere or other shape. If the stems get too long they will bend over. You can easily prune the stems, cut at will. New shoots will appear.
Indestructable house plants
Thanks to MShades for the photo