The Leyland cypress tree is a fast-growing evergreen that is hardy to plant in USDA growing zones 6 through 10, where the winters are mild. The tree reaches up to 50 feet and grows in a column formation when pruned or in a pyramid formation when left to grow naturally. The Leyland cypress is easily propagated by taking semi-hardwood cuttings in midsummer through early fall. Choose sections of new growth that is beginning to mature and is disease-free.
Disinfect all cutting tools by washing them with isopropyl alcohol and allow the tools dry before using them on the tree. This will prevent contaminating the tree with disease.
Cut 6-inch semi-hardwood cuttings with a sharp knife from the top part of the Leyland cypress where current growth has begun to mature and harden. Place the cuttings in a plastic bag with a damp paper towel to prevent them from drying out.
Fill a rooting tray or container with sterile rooting medium or mix equal portions of course sand, peat moss and perlite. Moisten the medium with water so it is damp but not wet.
Dip the cut end of the Leyland Cypress stem in rooting hormone as this will stimulate root growth. Stick the cutting into the rooting tray at a depth of 2 inches. Lightly firm the soil to hold the cutting in place.
Mist the cuttings with water and place a clear plastic bag over the tray to keep the humidity levels high during the rooting process. Place the tray in a warm location that has indirect sunlight.
Monitor Leyland cypress cuttings to make sure the soil does not dry out. Open the plastic covering several times a week to refresh the air around the cuttings. Spray the soil with water as needed.
Transplant the cuttings into individual growing containers filled with sterile potting soil once the roots have formed to 1 inch in length. This could take four to eight weeks. Continue to grow the cuttings indoors for the first year.