Certified GKH Gardening Expert
Spurge is also known as Euphorbia. You are in Zone 10 and shouldn't have any problem leaving it in the ground over the winter, but if you want to protect it, you may wrap it lightly in some kind of insulating material. It needs some water, but don't water it from the top and don't let it get soggy, or get completely dry. Also, beware of the sticky substance within the stems - it could cause skin irritation.