It it works, it is a miracle. Rhododendrons are never rooted this way.

Most evergreen rhododendrons such as Nova Zembla may be propagated from stem cuttings. Cuttings are best taken in the early fall from new growth that is just beginning to harden off. Generally, softer wood roots more readily than harder wood, though the softer the wood, the more likely it is that problems will occur with fungus diseases. Cuttings are taken in the morning when full of moisture. The cuttings are usually terminal cuttings with one whirl of leaves. Remove all but 3 or 4 leaves and cut the remaining leaves in half (to reduce the leaf area). Remove any flower buds but not foliage buds (flower buds are larger). Wound the portion of cutting that will be in the soil with a potato peeler on each side, about 1/2" to 1", just deep enough to cut through the bark. Dip the cutting in a rooting hormone containing indolebutyric acid makes rooting easier. The exact formula depends on the hardness of the cutting and the difficulty in rooting the cultivar you are tying to propagate. If the rooting hormone is too strong, roots may form but the top may never break dormancy and start growing. If the rooting hormone is too weak, the roots my not be sufficient for the top, so this is a crucial step that come from experience with each variety. For Nova Zembla, use a rooting hormone such as Dip 'N Grow. Dip 'N Grow is a concentrate. You must dilute it in the ratio 1 part hormone to 5 parts water. Let the wounded part of the cutting stay in the hormone dip for at least 5 seconds and then remove.

The cutting is wounded just before placing in hormone dip. Then the cuttings are placed in a flat of sterile media containing a mix of 50% peat moss, and 50% horticultural perlite or vermiculite. The flat is placed in a polyethylene bag with struts to keep bag away from the foliage and placed in a light area with no direct sunlight. The flat is rotated once or twice a week to compensate variations in light and temperature. Usually bottom warmth of 70-75°F is used to encourage root growth. Rooting usually takes about 3 to 4 months for large-leaf rhododendrons such as Nova Zembla. Once the cuttings have rooted, pot or transplant them to flats containing a sterile mix of 60% peat moss and 40% perlite. When in the liner stage, fertilize once a month with an acid-based azalea plant food like Peters at half the rate on the package. Removing terminal buds promotes sturdy well-branched plants.

For an illustrated description of what to do visit:

Rooting Rhododendron Cuttings - Potomac Valley Chapter of American Rhododendron Society

Here is a link that might be useful: How to grow rhododendrons and azaleas.

Hi, Rhodyman!
What a wonderful explanation!! That's very helpful! I tried it and it worked! :)
Have you a similar method for azalea cuttings?

Evergreen azaleas are even easier than rhododendrons. Deciduous azaleas are tricky since they tend to go dormant after rooting. People say that even if they do go dormant, after a year or two they eventually come out of it. Many people give up the first summer. Apparently if you wait they will be OK.

I recommend sticking with Don Hyatt's procedure. (pun intended)

Here is a link that might be useful: Don Hyatt on propagating Azaleas & Rhododendrons

Oh! that's nice! Thank you - and seems so easy! But what means "Even after they are well rooted, still keep on the "dry side" ...." ?? Dry side? where is it?
And for the dormant cuttings, do you think that it will always do now, in the end of winter?

The results depend on the variety, the ability to avoid disease contamination and the time of sticking. It is a percentage thing. Very few people get 100% results, but by sticking at the optimum time you can get the percentage higher. So when they are doing dormant cuttings, it is not out of choice, but to save material that would otherwise be wasted. In return, they expect a lower success rate, but an acceptable rate to make it worth the effort.