How to Dwarf a Tree

Detach a foot-long woody shoot from a healthy specimen of the tree you want to dwarf, during its dormancy period. Do not harvest frozen or damaged scion wood. Choose a shoot that includes two or more buds. Trim off the buds at the tip and base of the shoot. Store the scion cutting in a box filled with moist sphagnum or peat moss, or wrap it in damp paper towels and place it in a plastic bag. Keep it in a refrigerator or in a cool cellar that has not been used to store fruits and vegetables.

Select a suitable dwarfing rootstock for your cultivar. For example, dwarf pear (Pyrus) trees traditionally grow on quince (Cydonia oblonga) rootstock. Dwarf apple (Malus) trees grow on the Malling 7, Malling 9, Malling 26, Malling 27, Budgovsky 9, Geneva 11 and Geneva 16 apple rootstocks. Each variety of rootstock has its own strengths and vulnerabilities, though, so discuss the best options for your area and tree type with your local nursery or cooperative extension.

Make a cleft graft for flowering or fruiting trees during winter or early spring while the scion and rootstock are in their dormant season. Use straight-grained dwarf rootstock 1 to 4 inches in diameter, and use a 1/4-inch diameter straight scion, 6 to 8 inches long with at least three buds. Cut the dwarf rootstock cleanly perpendicular to the main stem and hold the cleft open with the tool. Use a clean clefting wedge to make a 2- to 3-inch split down the center of the dwarf rootstock. Starting just under the scion's lowest bud, make two tapered cuts about 1 to 2 inches long. Prepare two scions for each graft, and slide one into each end of the clefted rootstock. The tissue between the inner bark and the wood of both the scion and the dwarf rootstock should touch. Remove the tool and allow the dwarf rootstock to close over the scion and hold it in place. Seal the cut surfaces with grafting wax, paint or tape.

Use a whip or tongue graft when the dwarf rootstock and scion are close in size and you are using highly compatible species such as apple and pear. Both scion and dwarf rootstock should have a diameter of 1/4 to 1/2 inch. When whip grafting on dwarf rootstocks, follow the same basic procedure as the cleft graft but use only one cut, 6 to 8 inches above the roots, to give the dwarf tree greater support by planting deeper. Remove all buds below the graft. When planted, the scion should remain 2 to 3 inches above ground so it does not take over the dwarfing root.

Plant the dormant dwarf grafts into well-drained soil with the top bud above the soil line, leaving 12 to 16 inches between trees and 2 1/2 to 3 feet between rows. Tie the young dwarf trees to tree-training stakes with soft twine or chain ties to give adequate support to the brittle roots and encourage early fruiting. Minimal pruning promotes strong and productive trees and quality fruit.