Satsuma Mandarins are some of the hardiest citrus trees.  I have overwintered mine in Pennsylvania in an unheated greenhouses with no winter die back.  I do use woven fabric to "double cover' the plants in the greenhouse, providing an extra layer of protection. 
 
Growth Habit- Plants only reach about 10 feet 
 
3 inch fruits are easy to peel and are harvest in late  October in Pennsylvania.