Branching Out
Deeply Rooted
I have always associated the leaves hanging down in winter with a lack of moisture. This article does a good job of explaining how difficult it can be for rhodos to stay hydrated when the ground in frozen solid:
Why Rhododendron Leaves Roll Up in Cold Weather
Noticed your rhododendron leaves roll up when it's really cold in winter? Learn why leaves roll up in extreme weather & why it may be good.
gardenmentors.com