How to Split the Bark on a Crabapple Tree

Damaged crabapple trees can be revitalized through cleft grafting.

Flowering crabapples are prolific bloomers, stunning specimen trees also appreciated for their small, decorative fruits. Also valued by apple growers, crabapples produce abundant blossoms and compatible pollen that can greatly boost apple fruit set. Established crabapple trees can be "top-worked" or revitalized by removing and replacing old branches if top branches weaken or suffer damage. This is done through cleft grafting, a process that begins with carefully splitting or creating a cleft in the wood of an existing branch.

Things You'll Need

• Crabapple scions (budded, ready to open)
• Top-worked crabapple tree
• Garden gloves
• Grafting chisel
• Small mallet or hammer
• Grafting knife
• Grafting tool or screwdriver
• Grafting compound
• Branch brace (thin wooden stick)
• Twine or garden tape

Instructions

1. Start with a freshly cut branch surface that's clean and flat, preferably a branch that's one to two inches in diameter.

2. Chisel the cleft in the center of the branch by gently tapping the chisel into the wood. Work slowly to avoid splitting the branch too deeply.

3. Cut scions to include three buds, using the grafting knife. Whittle a blunt grafting wedge about 1 1/2 inches long on the cut end of each scion. Make a long sloping cut on one side, starting about a quarter inch below the bottom scion bud. Make a blunter, shorter cut on the opposite side. Leave bark intact on the outer part of the scion wedge.

4. Insert a scion from each side of the graft cleft, using the screwdriver or graft tool to pry open the cleft. Place each scion so that the exposed inner bark of both scion and tree make good contact by tilting each scion slightly, and the thick, bark-covered side of the scion should be facing outward.

5. Cover the scion-tree graft unions with grafting compound, making sure that the cleft is covered for its entire length to prevent disease.

6. Tie a small supporting brace to both the tree branch and the scion, using twine or plastic garden tape, to prevent damage or breakage while each new scion branch gets established.

Tips & Warnings

• Cleft grafts should be no higher than four to six feet above the ground, to avoid creating a treetop that's too high, and within two to three feet of the trunk or main branches.

• Avoid creating a pointed grafting wedge, to prevent branch or bark splitting and to encourage the graft's success.

• Add different varieties of crabapple branches to an existing tree to create a unique, personalized crabapple.

• Prune crabapples in late winter or early spring, before new growth begins. Prune no more than 25 to 30 percent of the entire crown to avoid stimulating sucker growth.

References

• University of Minnesota Extension: Grafting and Budding Fruit Trees
• The Morning Sentinel: The Art of the Apple-Tree Graft
• North Dakota State University Extension: Questions on Crab Apple
• Clemson University Extension: Crabapple