Lychee (Litchi chinensis) trees are treasured in Hawaii for their good looks and sweet, pungent fruit. The dark green and well-formed ornamental fruit tree yields clusters of round, red fruits. Brought to Hawaii from its native home of China, the tree is grown successfully on the U.S. mainland as well -- in U.S. Department of Agriculture plant hardiness zones, 10 through 11. Home gardeners, however may be put off by propagating pains. Propagating from seed may mean waiting 25 years for fruit. Traditional grafting and budding techniques typically fail. Stem cuttings aren't much easier, requiring constant misting. You can, however, take an easier path by propagating your backyard lychee with a simple air layering technique called marcotting. The tree will perform most of the labor, and you won’t have to babysit your handiwork. And you'll have fruit in two to five years.
Choose a vertical-growing branch of the lychee tree to propagate in early summer. An upright branch will allow rainwater to drain freely away from the air layer. Look for an unblemished branch about 3/4 to 1-inch in diameter with fully matured leaves. A branch with full sun exposure is best.
Use a clean, sharp knife to strip a ring of bark about 1 to 1-1/2 inches wide from an easy to reach spot of the branch. Scrape off the thin, white material, or cambium layer, beneath the bark to completely expose the wood. The break in the bark and cambium layer prevents sap from flowing to the upper portion of the shoot. This forces the upper branch to produce roots at the wound site in order to survive.
Dampen a handful of sphagnum moss and squeeze out the excess water. Mold the moss tightly around the wound to create a patch about 2-1/2 to 4 inches wide and about 1/2 inch deep.
Enclose the moss loosely with two or three layers of plastic wrap to hold it in place but still allow room for roots to form. Firm the plastic tightly to the branch on either side of the wound to prevent rainwater from entering the air layer. Roots won’t form in a wet environment.
Cover the plastic with a 12-inch length of aluminum foil, shiny side up to keep birds from pecking at the air layer. Wrap the foil loosely around the air layer and mold it firmly to the branch on both sides.
Remove the foil two months later when the air layer is fat and feels hard due to developing roots. If the roots are still small, replace the foil and give the air layer another month. If you see plenty of healthy roots about two or three inches long, it’s safe to harvest the young tree.
Cut the branch from the tree with clean, sharp pruning shears just beyond the lowest roots. Loosen the plastic wrap carefully. Peel it back enough to allow water to seep into the roots. Soak the root ball in warm water for about 15 minutes to hydrate the brittle and fragile roots. Remove the plastic completely.
Plant the lychee tree in a 1-gallon pot of soilless potting mix with the top of the root ball about 1 inch below the soil surface. Water thoroughly to evenly moisten the soil surface, but not enough to make it soggy or wet. Set the plant in a shady spot, protected from wind.
Drape a clear plastic bag over the branches and foliage. Poke about 20 holes in the bag to allow for good air circulation. Mist the tree twice daily to provide the high level of humidity that lychee requires.
Water just enough to keep the soil surface barely moist to your touch. Feed the lychee about 6 weeks after planting. Dissolve 1/2 teaspoon of water soluble 20-20-20 fertilizer in a gallon of water. Water the soil slowly with the solution until it runs out the drainage holes. Repeat every 8 weeks throughout the growing season.
Gradually acclimate the tree to full sun when new growth appears. Step it up to a 3-gallon pot about one month later, or plant it in a well-draining, fertile spot in full sun.