This publication from the Montana State University Extension also indicates that R. rugosa rubra is hardy to zone 2. Could someone make the zone change? Thank you.

http://store.msuextension.org/publications/YardandGarden/MT199603AG.pdf

The following online publication lists R. rugosa as hardy to zone 2.

http://public.wsu.edu/~lohr/wcl/shrubs/rosarug/rosarugosa.html