I don't know what rhododendrons you planted, but they may be okay without much more protection. I found the Finnish hybrids to be extremely hardy. Also I don't know what soil mixture you used. I am glad that you made a berm. I used oak leaves and pine fines to mulch. The wood chips are bad because they use a lot of nitrogen which they get from the soil as they decompose. Notice yellow grass which has sawdust spread on it. Wood chips hurt the soil! If you really have a wind problem in the winter, try using a burlap fence around the bed where the rhodies are planted. I did this and often used a cheap plastic fence from Home Depot as a backing. Good luck and hope this helps. Ted Nyquist