Magnolia trees can be propagated by taking semi-hardwood cuttings from mid-July through early fall, after the tree has gone through a growing period. Semi-hardwood cuttings are taken from current-year branch growth that is changing from soft and green to stiff and mature. Patience and time is needed when rooting magnolia trees, as several varieties are considered difficult to root and may take up to 12 months to produce root growth.
Take semi-hardwood cuttings from the magnolia tree in mid-summer through early fall. Cut a 4-to-6-inch cutting from fresh, new branch growth. Semi-hardwood cuttings are taken from the ends of branches on the upper portion of the tree.
Mix a rooting medium by combining equal parts of sterile peat moss, course sand and perlite. Dampen the mixture with water and fill into a rooting tray.
Remove the leaves from the lower half of the stem and wound the lower end of the cutting by making a half-inch slit into it with a sharp knife. Dip the cut end into rooting hormone designed for hard-to-root trees.
Stick the cutting into the rooting medium to a depth of 2 to 3 inches. Make sure to leave enough space so the leaves of each cutting do not touch.
Place the cutting tray under a misting unit or manually mist the tray with a sprayer each day until the roots develop. The cuttings will form roots in six to 12 months.
Gently pull on the cuttings to see if there is resistance from root growth. Plant rooted cuttings into individual potting containers filled with sterile potting soil to increase the cuttings' root structure. Continue to grow the cuttings until spring when they can be planted outdoors.