Grafting older trees provides new pecan strains in established orchards and replaces the top growth of wild pecans with commercially important varieties. Where pecans co-exist with cattle, grafting saplings above grazing height improves the chances of the scion's survival. The inlay bark graft--the most common for top-working pecan trees--works best on pecans between 3 and 12 inches across at chest level.
Inlay Bark Grafting
Collect scions from known pecan varieties by clipping vigorous branch tips and top growth with pruning shears. Harvest scions in late winter. Wax the cut ends and store the scions between moist paper towels. Refrigerate in a folded--but not sealed--plastic bag until needed.
Graft in late winter or early spring before pecan buds open. Cut trees 3 to 5 inches in diameter straight across with the pruning saw at about 6 feet above ground level. If possible, save a strong branch on the south side to shade the trunk. Cut the top several inches above the branch.
Use the knife to shave away rough outer bark from an area three or four inches wide and several inches long. Leave enough outer bark to shield the cambium yet flex when pulling the bark away from the trunk.
Carefully cut a pecan scion with the knife for three inches across the bottom end in a long diagonal slice. The cut surface should be perfectly straight and flat. Place the cut surface vertically against the shaved section of bark on the host trunk. Mark the outline carefully with the pocket knife. Use the knife to slice through the bark along both lines. Flare the cuts to the sides at the bottom to form a strong hinge.
Taper the bark side of the scion with the knife to expose sapwood and cambium for about three quarters of an inch. Lever the bark strip away from the trunk and slide the scion into place with the cut surface against the sapwood. If the bark won't slip tap it carefully with a hammer. Press the bark strip against the back of the scion. Use one or two small nails to secure the scion to the tree or wrap the area with degradable string or tape.
Seal the top cut with grafting wax. Good grafting wax softens at body temperature--keep some in a bag in your pocket to keep it warm and workable. Cover the entire grafted area with a layer of tin foil. Press the foil carefully around the base of the scion.
Cut a small slit in the bottom of a clear polyethylene bag and slide the scion tip through. Pull the bag carefully over the grafted section of the tree. Repair a loose fit around the scion by wrapping with a section of rubber band. Use grafting tape or electrician's tape to secure the bag below the top-worked graft.
Things You Will Need
- Pruning clippers
- Viable scions of known pecan cultivars
- Paper towels
- Ziploc bags
- Sharp pocketknife or grafting knife
- Pruning saw
- Grafting wax
- Aluminum foil
- Clear polyethylene bags
- Rubber bands
- Garden twine
- Grafting tape or electrician's tape
- Graft two sides of the same top cut for a better success rate. Prepare both sides, graft one scion and fasten it with a small nail. Graft the second scion and quickly seal and cover the graft. Remove the weaker graft when the tree heals and one graft dominates.
- Top work larger trees by grafting the central leader and several large branches. Remove 70 per cent of the tree's limbs before grafting. As the grafts heal and the new scions take over, remove the old limbs that remain. This process could take several years.
- Graft quickly and accurately. If bark or sapwood dries the graft will not take. Gaps between graft and hosts cause failures. Practice on freshly cut branches before top-working important pecan trees.
- Don't use a chainsaw for the top cut. The bar oil could prevent the graft from healing.