There are three of them in this pot. They were grown from seeds taken from a rooted cutting. There were no other flowering Euphorbia in the area, so I think it is self-pollinating. I keep it on the moist side while it's growing, and almost no water when its cold.
Not cold hardy. They were exposed to about 3-6 hours of freezing temperatures a few years ago, and took a couple of years to recover.
Cuttings are slow to root, but I've had a 100% success rate.
People often mistake these for cactus. They are from Africa and developed in similar conditions as cactus. They have a milky sap that runs heavily in the growing season, and you do NOT want to get that sap on your skin, because it BURNS LIKE FIRE! Well...it stings pretty hard, anyway. Unlike cactus spines which tend to snap off in your tender flesh and fester, this bad boy will rip you open like a filet knife and keep it's spines for it's next attack against you. You'll probably want to keep the kids and dogs away from it.