Detailed Explanation of Air Layering Propagation Methods and Technical Key Points for Southern Magnolia

1. Items needed: potting soil (by volume, the ratio of garden soil, moss, and aged rice husk ash is 1:0.5:1, mixed with water until it forms a ball when squeezed by hand, with a slight water mark showing but not dripping); pruning shears; grafting knife; plastic film (30 cm long, 25 cm wide); small coir rope, etc.

2. Mother tree selection: choose a mature tree 160-200 cm tall (for ease of operation), growing vigorously with relatively dense branching.

3. Layering time: early April to early May is most suitable. At this time sap flow is vigorous, bark is easy to peel, and it favors wound healing and rooting.

4. Layering method: first, select a well-developed 2-3 year old branch, 0.8-1 cm thick, from a densely branched part of the canopy; girdle it at 10-15 cm from the base of the branch, with a width of 2-3 cm, and scrape off the cambium to prevent the bark from healing back together. Wrapping is done step by step: first tie one end of the plastic film tightly with fine rope at 8-10 cm below the wound, then roll it upward into a cylinder shape, then fill in the prepared potting soil until it reaches 6-8 cm above the girdled area, squeeze firmly from outside the film by hand so that the soil ball forms a spindle shape, finally tie it tightly, and bind a few loops around the outside of the soil ball.

5. Management after removal from the tree: roots can develop half a month after layering, and for all surviving seedlings the root system can be seen outside the plastic film. Remove from the tree from June to September, transplant with the soil ball, and water thoroughly to settle the roots. Afterward, pay attention to drought prevention and watering, and at the same time apply additional dilute organic fertilizer; by late October they can be planted in place.