10 favorite votes.  

White, near white or white blend Large-Flowered Climber.
Registration name: White Mountains

Bred by E.B. Risley (United States, 1958).

Climber, Rambler.  

White, light pink outer petals.  Double (17-25 petals), in large clusters bloom form.  Spring or summer flush with scattered later bloom.  

Climbing.  

USDA zone 3b and warmer.  Hardy.  vigorous.  Prune after flowering is finished.  This rose blooms on old wood.  

Mike Lowe of Lowe's Roses says the flowers are white, becoming greenish, double, small and borne in clusters...
Since the parent of this rose is hardy to Zone 2, it would seem possible that White Mountains should be hardier than Zone 4.