which PF lists as hardy to Zone 9b. You might need to protect it if it's not under the eaves or whatever. I have the luxury of not worrying about such matters here in Zone 11.
I have a green version of that plant and it's a nice robust grower pretty much year-round. Easy to start from cuttings, though they may not root right away. Responds to fertilizer and likes more water than many Euphorbias, just be sure the soil has excellent drainage. Should make a nice landscape specimen in a relatively short time.
I have a green one of those too. About 3 feet tall and still in a pot. It just survived outside during 4 nights of low to mid 20s T here in Mesa, but it was sitting right next to the house and under a patio roof - according to my wall thermometer it might never have gotten below freezing close to the house, so that is probably why it made it through so well.
As Baja_Costera writes a good grower, and very pretty plant. I need to really watch it in terms of watering in the summers here as it gets really hot even if it is in the shade except for a few morning hours. I had hesitated to plant is because of worries about happening exactly what happened here over last weekend, those very cold nights, so that was lucky, but it will have to go into the ground somewhere this spring.