A makeshift bucket of twigs cut from pruned branches hangs in the green apple tree I’m converting into a red apple tree.
For the past many posts, Your Small Kitchen Garden has focused on grafting and pruning apple trees. Two posts back, we looked at equipment I use to graft red apple stock onto my green apple tree—and I introduced a video that shows me assembling a graft. In the last post, I listed guidelines I follow as I choose which branches will host scions in the green apple tree. This post provides written, step-by-step instructions for assembling a graft. Though I’m talking about apple trees, this technique will work on just about any deciduous fruit tree.
I’ll assume that you’ve been pruning apple trees and have several branches from which to harvest grafting stock. Make scions from last year’s growth. Last year’s growth is at the ends of the smallest branches. Last year was very dry here, so branches grew only three or four inches beyond the previous year’s growth. In wet years, my apple branches have grown a foot or more. In any case, cut and save a dozen or so twelve-inch twigs off the ends of your pruned branches, and put these in a bucket you can hang from a branch.
If there are no fruiting spurs on the section of branch you harvest, you’re probably looking at last year’s growth. If you can spot a scaly ring in the bark, it most likely marks where the terminal bud spent last winter; everything after it should be last year’s growth.
Haul the twig bucket, a gear bucket, and a pruning saw up in the tree and perch so you can easily get both hands on the host branch without falling out of the tree. I like to work on a step ladder which provides a steady base and reduces my need to climb the tree. Standing on branches erodes the bark, and increases my chances of damaging small twigs and existing grafts.
7 Steps of Grafting Apple Trees
Cut the host branch—Make as clean a cut as you can, perpendicular to the branch. Leave a stump just two or three inches long. For very thin branches (a half inch is about the thinnest it’s practical to graft onto), I might use bypass pruners or loppers, but in most cases I use a fine-toothed saw so as not to crush the branch or its bark. With a saw, cut about three quarters of the way through from one side, then remove the saw from the cut, flip it, and finish the cut from the other side. I’ve seen better pruning saws than I own cut cleanly through a branch in a few strokes without a back cut… the quality of your tools will influence your technique.
Split the host branch—Use a sharp knife, align the blade across the center of the stump, and gently rock it while pressing it into the cut end. I try to split along a line that’s perpendicular to the trunk branch from which the stump grows. For a narrow stump, make the split about and inch long. For a heavier stump, it might take a three-inch split to provide enough play to get scions into the crack.
I liked this small branch as the host for a graft; it had a gaping hole in the bark that I was able to remove, and set a graft just blow it. The bypass pruners deformed the stump a little, but I’m confident the graft will take anyway. Notice that I split the stump across the limb to which it’s attached.
Make a scion—Whittle a scion from the harvested grafting stock. Start at a leaf bud three-to-seven inches from the terminal bud of a twig. Whittle a wedge starting at that leaf bud and getting narrower toward the bottom of the scion. The wedge—from leaf bud to the end of the scion—should be about a half inch long (see photos).
Start whittling on one side of a leaf bud, but make sure you leave the bud intact. A finished scion tapers for about a half to three quarters of an inch from the bottom leaf bud down to a chisel point. The leaf bud will sit about even with the end of the stump and will point out from the side of the stump.
Insert the scion into the stump—Spring the crack open and work the whittled wedge into one side of it. The leaf bud at the top of the wedge should point out, and end up aligned with the top of the stump. I use the point of my utility knife to spring the stump open. If you do this, be cautious; when you flex it too much, the knife blade will break. For thicker host branches, I sometimes use a screwdriver to hold the crack open as I insert scions (explained in my last post, Strategies for Grafting Fruit Trees). Make sure the edges of the bark of the scion align with the edges of the bark along the crack in the host stump.
I use the tip of my utility knife to flex the stump open as I insert the first scion into the crack. The first scion usually holds the stump open enough that I can easily insert the second scion. Aligning the bark at this point is crucial.
Add a second scion—Whittle a scion to match the first one and work it into the other end of the crack in the host stump. Chances are, you won’t need to flex the crack open this time as the first scion will hold it wide enough for the second scion to fit. You may need to readjust both scions several times to make sure their bark aligns with the host stump’s bark.
Wrap the graft—I once bought and messed with grafting tape, but didn’t have any luck with it. However, while creating this series on grafting, I learned that you can coat a new graft with wax, then wrap it with grafting tape to protect it from the elements. This requires heating the wax which seems inconvenient, especially on a cold day… but I’ve never tried it, so don’t let my inexperience keep you from finding a better approach.
I use cotton twine and tree wound dressing. Tie the twine around the stump at the bottom of the crack (I use a clove hitch, but any knot will do). Then, wrap the twine around the stump, working toward the leaf buds on the scions, and laying each successive loop of twine tightly against the preceding loop. Get the last loop of twine as close to the end of the stump as you can without running it up onto the leaf buds of the scions. Finish it off by running the end of the twine through a loop, pulling it tight, and cutting off excess twine.
I tie a clove hitch at the bottom of the split, then catch the end of the twine in the first loop or two as I work my way up the stump.
Waterproof the wrap—Use a water-based tree wound dressing, and coat the cotton twine wrapping. Also, dab tree wound dressing on the end of the stump so no wood shows through. It’s ok if dressing runs into the crack and coats the bottom leaf buds on the scions; make sure you coat all the twine and the stump’s split end.
I use a water-based sealant called Treekote tree wound dressing made byWalter E Clark & Son in Orange, Connecticut. Don’t use the stuff to dress wounds left by pruning, but waterproof your graft with it to keep things from drying out while the scions knit themsleves to the host stump.
When Your Fruit Tree Grafts are Done
A successful graft wakes up more slowly than the rest of your small kitchen garden. There may be leaves on the rest of the tree for a month or longer before your scions show signs of life. Usually, the first change appears in a scion’s terminal bud; if that opens up, the graft has taken and is likely to knit up with the stump.
Once leaves emerge, remove the protective wrap from the stump. I use the razor-sharp utility knife to slice part way through the coils of twine without going as deep as the bark. This cuts through the loop of twine I tucked under at the end of the wrap and I can unravel the whole wrap from there. Unwrap gently. Sometimes the twine sticks to the tender bark; if you work slowly, you can unstick it without doing too much damage.