This is an open pollinated R. kochiana seedling. As you can see from the size (I am about 5-10), it is completely hardy. The mother is not listed in Modern Roses 11. In Modern Roses 9, it is listed as possibly a F2 cross from R. palustris X R. spinoissima. 14 chromosomes.
R. palustris is listed as growing to 8 feet. R. spinoissima is listed as growing 3-4 feet. R. kochiana is listed as growing to 3 feet.