How to Repair a Broken Tree With Grafts

By
Jonathan Landsman
Jonathan Landsman
Jonathan Landsman is a professional horticulturist and former city planner for the NYC Department of Parks & Recreation.
Learn more about The Spruce's Editorial Process
Updated on 06/21/22
Reviewed by
Andrew Hughes
andrew hughes
Reviewed by Andrew Hughes
Andrew Hughes is a certified arborist and member of the International Society of Arborists specializing in tree heal care. He founded and runs Urban Loggers, LLC, a company offering residential tree services in the Midwest and Connecticut.
Learn more about The Spruce's Review Board
Grafting a tree branch
Kristian Septimius Krogh/E+/Getty Images
Project Overview
  • Working Time: 1 - 2 hrs
  • Total Time: 1 - 2 hrs
  • Skill Level: Beginner

Maybe your landscaper (or your spouse) rammed the ride-on mower into your Kentucky yellowwood tree. Or, you accidentally ground up a few fairly important surface roots yourself. Trees can also sustain damage due to winter splitting from heavy snow loads or animal damage (like buck rub or rodent chew). Whatever the cause, tree surgery may be needed. Tree grafting is a laborious undertaking, but for a special tree with a major wound, the task may be worth it to you.

Tree Grafting Basics

If you inspect an old wound on a tree—resulting from impact damage or a broken limb—you might notice rolls of “flesh” on the rim of the scar. When wounded, woody plants recover from the outside in because the actively dividing cambium (or skin) is now only present around the edges. The tree then attempts to grow over the deadwood in the wound, surrounding it with healthy wood and closing it off from the rest of the tree, thus preventing any infections or further decay (this is called compartmentalizing). Working from the edges to the middle, this can take many years to complete. For this reason, it's important to make clean cuts when pruning to keep the resulting wound as small as possible.

Grafting involves placing a makeshift Band-Aid over the wound to form a bridge that the cambium can adhere to. Grafting is usually only required for a large wound, aiding in the recovery process and covering the damaged site. The result yields a faster recovery time and prevents insect damage or disease from moving in.

Featured Video

What You'll Need

Equipment / Tools

  • Garden knife or shears

Materials

Keep in mind that the supplies you need depend upon your approach to grafting.

  • Small scions
  • Brads
  • Grafting wax
  • Small plants (suckers)
  • Tree cage or cylinder

Instructions

  1. Fix the Tree with Bridge Grafting

    Bridge grafting is one of the most common ways of caring for wounds on the trunk of a tree. In bridge grafting, an evenly-spaced set of twig-sized scions (or bridge wood) is obtained either from the tree itself during a prior growing year or purchased from a nursery.

    To graft, first trim the loose bark from around the wound, creating smooth edges. Next, slice a few parallel cuts above and below the wound, peeling back the bark to make flaps.

    Gently but firmly work the end of each scion under the flaps. Nail the ends in place with small brads to secure them. Depending on the size of the wound, you may need several scions to complete the bridge.

    Cover the grafts with grafting wax to prevent the wound from drying out. Shave off any buds that form on the scion during the repair process.

  2. Try Inarching to Repair the Wound

    Inarching is a way to repair wounds that reside on the lower part of the tree, including a wound to the root. You can even replace entire root systems by using this tactic. Inarching involves taking the small plants (or suckers) that reside at the base of the tree and joining them to the trunk in a similar fashion to bridge grafting.

    For this process, select suckers that are at least a 1/4 inch in diameter. Cut the sucker so that it's a 1/2 inch longer than the wound area.

    Create a flap in the tree's bark, similar to the flaps used in bridge grafting, so that you can slide the sucker under it to create a girdle. Cover the area with grafting wax and protect the tree with a cage or cylinder to prevent future damage.

  3. Cable the Tree

    The last type of wound repair is used when two limbs on a tree develop a weakened crotch or poor attachment point. Cabling secures the branches that could otherwise split the tree, leaving a large, ragged wound. Cabling is usually performed by a skilled arborist and involves tying two branches together with either an artificial material, like a cable, or a woven “rope” made of flexible scions grafted to the interior of the crotch.

    Instead of using a man-made cable, which can decompose due to sun and weather, a rope of living scions grows into the tree's structure, fusing and strengthening the organism. Cabling is not usually used on ornamental fruit trees; it is more often performed on very large multi-stem trees.