What does the air layering propagation method for azaleas mean?

The "air layering" propagation method for azaleas is also called the plastic bag air layering method:

First, choose any part of a vigorous 1-3 year old branch. The length of the girdled ring section can be determined by the thickness of the branch. If the branch is about as thick as a chopstick, the length of bark to be removed can be 0.5-1 cm; for slightly thinner branches, the length can be shorter. For the peeling tool, you can use the nail of your right thumb: after selecting the spot, gently scrape from top to bottom, or use a small knife to score a ring at the upper and lower ends, then gently peel off the bark.

Second, after girdling, use a piece of plastic film about 6-8 cm long and about 5-6 cm wide to wrap around the girdled area, forming a cylinder, and first tie the lower end firmly with string or lead wire. The tying point is about 2 cm below the girdled area. Gradually add slightly acidic soil that has been mixed with water into the plastic cylinder. If 1/5 moss is added to the soil and mixed in, the effect will be better; it can maintain constant humidity inside the plastic bag, help prevent drying, and promote early healing and early rooting. When the soil is filled, tie the upper end firmly as well with string or fine lead wire, forming a shape about the size of an egg, and leave it outdoors to be exposed to sun and rain, while carrying out routine maintenance such as fertilizing and watering. Usually, when watering, it is best to spray some water on the leaf surface so that moisture slowly seeps from the branches and leaves into the plastic bag, increasing the humidity inside the bag, but be careful not to make it too wet; it can be kept on the drier side, because if it is too wet, healing and rooting will instead be slower.

Third, the timing for adopting the above "air layering" method: spring azaleas such as Western azaleas, hairy-leaf azaleas, etc. can generally be layered after the flowers fade, and summer azaleas can be layered in June after the flowers fade. Generally, after 3-4 months, roots can form, and the survival rate can reach over 90%. Then cut it off together with the plastic bag, gently remove the string or lead wire, peel off the plastic film, and plant it separately in another pot. In this way, it becomes a new azalea plant, and it can bloom with bright flowers the next year.