Mirjana Bulatovic-Danilovich, Consumer Horticulture Specialist, WVU Extension Service Agriculture and Natural Resources
There are several ways to propagate magnolia trees. You can do that by seed, clonal propagation by softwood cuttings, air layering, grafting in winter (bench grafting), grafting in spring (whip grafting, chip budding) or chip budding in summer.
Clonal propagation by softwood cuttings
Take 6- to 8-inch cuttings from the newly developing shoots. To prevent drying off, place them in a jar partially filled with water as soon as you cut them off.
Prepare the cuttings for rooting by removing all the leaves except for the two at the very tip of the cuttings. If the leaves are too large, cut part of the leaf.
Prepare the rooting bed using a 10- to12-inch deep plastic container, which is deep enough to accommodate the cuttings. Drill drainage holes in the bottom of the plastic container and fill them with rooting medium. The rooting medium could be a mixture of one-third coarse sand, one-third peat and one-third vermiculate, or a peat and vermiculate mixture, or simply coarse sand.
Using a pencil or stick, make holes in the medium that will be wide enough to receive the cuttings. Dip the cuttings into the rooting hormone Indol-3-buteric acid that comes under several trade names (Rootone®, TakeRoot®, FastRoot®, Dip&Grow®, etc.). Place the cuttings into the rooting medium with the necessary spacing to allow for sufficient light interception by the leaves.
After setting the cuttings in the medium, irrigate and cover with a clear top or plastic to maintain the high-humidity environment. Keep them away from direct sunlight. It will take a few weeks for the cuttings to produce strong enough root systems to be transplanted into a larger container or directly in the garden.
It is best if air layering is done in early spring or late summer (September). Choose a one-year-old shoot and cut about 1/3 to 1/2 inch into it. Put some of the rooting hormone over the wound. Then, wrap moist (but not soggy) sphagnum/peat moss in a layer at least 2 inches thick around the wound. Wrap plastic around it and secure the ends with electrical tape.
The sphagnum moss must remain moist at all times, so check it frequently – under no circumstances should the sphagnum moss dry out. If that happens, the roots will dry out and the procedure will fail.
After a few weeks, as the roots develop, you will see them protruding through the sphagnum moss. At that point, cut off the shoot below the rooted end and plant it in a pot or directly in the garden. It may take two to three years for the new plant to start blooming; however, if the new plant was started from seed, the time would be much shorter.