Hi Guest
I have tried collecting cuttings of all the rhododendrons I fancied in our local country park but none of them survived. If it is your own plant you can try layering a young stem to ground level and cover with 2-3 inches of soil. Make a small lengthwise slit where the stem is to be buried. Anchor with a peg and stake vertically. Cut after 2 years. I tried cuttings from young growth, mid July to late August. Root in a cold frame or greenhouse, 2 part fine sand 1 part compost. Good luck! Patience is needed.