I just viewed a video with a grafting method using a power drill. A couple of years ago I removed an unproductive cherry tree and had I known this method, it would have been simple to rework to another variety.
He is starting with a ‘root stock’ that is already a good sized tree, drilling into the wood, chamfering the hole then using pretty hefty scions, trims them to proper size, exposing the cambrium. The narration is in Italian but the video makes the process very clear. There are certainly situations where this method would be appropriate and I would guess the success rate would be pretty high. It seems he had a preference for removing limbs and drilling into collar area which makes sense as that area would heal fast.
He also topped the tree and did a wedge graft at the top.
I have a question though, for those who may have more experience at grafting than I. Normally, grafting requires dormant scions, while ‘budding’ done later in the season gets cambrium union with fresh buds. Since this method seems to ensure a lot of cambrium-cambrium contact, what is the likelihood it could be used with non-dormant scions? Seems to me it would be owrth a try.
The issue w dormancy is indirectly cambium contact: more is better but your biggest concern is scion desiccation before it knits together. If you have a leafed-out scion unless you can keep humidity extremely high square yards of cambuim arent gonna help, the scion will be dead in a day or two. You might be able to get away with it by grafting during exceptionally wet weather, put in a bag around it for humidity, etc., but that is the big problem: leaves Lose a ton of water. Buds do not. So leafed-out scions have way less time to knit to rootstock before they dry out.
I really wasn’t thinking of scions with leaves, but with leaves trimmed as if to root it. Basically new green wood. I don’t know what that Italian fellow was using but he had considerable growth in just 40 days.
Someone has posted this same video before, and I think it is really neat.
One thing confuses me a tiny bit. When he cuts the bark off the expose the cambium layer, it looks like he removes the cambium. I thought the cambium was the bright green layer just under the bark, the part you see when you scratch a tender shoot with a finger nail. But when he trims he cuts that bright green off along with the bark and seems only to leave the solid wood at the beginning of the core. hmmm???
Well, my understanding is the cambium contact occurs basically between the “ring“ left on the trunk, and the very end of the bark left on the scion. The “plug” of wood at the end (where he removed the bark) is basically just to hold the scion in place with tension.
I have grafted during the growing months and yes remove the leaves. If grafted before mid summer the scions will grow more. The ones I grafted were with cleft or side grafts. I also wrapped with parafilm in most cases.
I had the same thought, he’s awfully hard on the cambium. But he’s not removing it all. The part inside the tree is just physical support, I think. So that doesn’t matter if he scrapes it or not. The contact is at the cambium on the rootstock. That’s the only place it can be. But given that he’s doing the graft right where an old branch was, I’m not sure what’s lining up.
My thinking is that pruning is recommended that be done at a branch collar rather than flush with the trunk is because cell growth is more active there and heals much faster. I would think that same cell growth would foster rapid cambrium fusion for the graft.
Also, he uses the drill method where no branch existed, but his chamfering method is different. It would have been nice to have an English translation for what he was doing.
I think it probable that more cambrium is exposed in the collar area. Thoughts, anyone?
Youtube can do a translation although it is not very good but better than nothing.
Here how it is done on a Windows PC. It might be different when using IOS or Android on a phone. Below the Youtube video there is the “Save” function and to the right of that is the “…” which opens the translate function. Once the language is chosen and “auto translate” is selected then closed caption (CC) needs to be selected.
I think @BG1977 and @fruitnut have it right…I think he probably IS removing all the cambium under the bark where he trims the bark off and is only using that stub for support. Then the actual cell producing area/cambium that is being relied on is the bottom edge of the bark he leaves on the scion. this bottom edge cambium appears to line up with the edge of cambium that is just millimeters inside the hole he drills, just under the bark ring left on the rootstock. I also think @RandallW is right…we all know it’s best to prune unwanted limbs right at the collar because cell growth is faster and better at those locations. So it stands to reason that grafting at those collar sites would also improve success rates. At least those are my thoughts?
That’s why he uses a counter sink router bit. By angling the edge there is a better chance of the cambium layer of the scion contacting the rootstock cambium when it is tapped in.
Useful discussion.
I notice that when drilling where there was no branch, he doesn’t use the router bit for chamfering and merely uses a knife, apparently to trim any ragged bark. I would guess that is because the hole does not expose as much cambium.
Oops, sorry, I checked again and he did chamfer one of those holes, but another on, no. Beats me why.
I plan on giving it a try, but with much smaller scions. I have a couple of trees with poor branching that could benefit from an additional branch or two.
I attempted a translation of the closed captions of the narration, but the cc was done with speech recognition software and that produces weird results even in English. Perhaps you can imagine the sort of gibberish you would get with Italian and then try translating to English. What you get is word soup. What I did get is that he was grafting four varieties of apples and had 70% success. Hell, I have a 95% success rate on apples using regular rind and whip and tongue grafts.
My success with peaches/nectarines has been only about 25% but it appears I have been grafting too early.