Answer: How upsetting! Your plants should recover just fine; luckily rhododendrons can send out new growth from old wood, so using the energy from their established root systems they should be able to generate new branches pretty quickly. You might want to tidy some of the worst damage and tidy the breakage points into clean cuts. To help them along, you might want to keep them lightly mulched and ensure they are adequately watered this summer, and topdress with compost or perhaps a slow release fertilizer specifically intended for acid loving plants. (These are not heavy feeders so do not exceed the amounts in the label instructions.) Another thing to keep in mind (if you have the chance) is that periodically brushing off heavy snow before it accumulates much is the best protection against breakage.
Finally, these plants are normally propagated from tip cuttings in the spring rather than from old wood -- these shrubs will probably send up a lot of new growth this year so you'll have ample opportunity to take cuttings if you need to.
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