I’m bench grafting apples and have a number of scion / rootstocks where their caliber is different.
The graft types I’ve seen proposed for this are:
Side graft (I assume ‘Side W&T’ is the same graft)
An ‘along side’ graft (Steven Edholm mentions as being like a scarf or lap joint)
Maybe a a splice graft with just one edge touching is also appropriate for minor mismatches? Happy to hear of other means to graft, too.
How do long term strengths of these grafts compare to each other?
How do the long term strengths of these grafts compare to a W&T or cleft graft where the diameters match?
What do you mean by long term? 1st season or 3 or 20? Are you worried about the graft getting ripped off with some new growth in strong wind or a few years later when ladden with fruit? Because it does not really matter after the graft takes and the two perts grow together propperly and build new tissue.
Well, yes. There is incompatible or poor rootstock (or even graft resistant ) and then there is a rule of thumb, that you use deep wedge or deep W&T in an extremely windy location, hence my third question. But if the rootstock is good and you don’t overload the tree in the next season, you should be (generally ) fine.
I have never grafted but the only time I had a graft fail on me was when I got some male persimmon from Hidden Springs Nursery. Their pawpaw came out of dormancy unlike One Green Worlds and the problem was more so an animal and the fence got to it. The wooden fence fell right on my pawpaw trees. My hardy kiwi are not out of dormancy yet but the first year they grew like crazy from them. For whatever reason my persimmon I got from there all failed. Again that is the only experience of the graft failing. They were super small so I wonder if they sent them before the graft was connected fully.
Sorry for the delay… we had an extended power issue.
Yes, worried about the graft union failing under snow load or strong winds… we can get both, and in abnormal times of the year. I’d probably look to others to define what the ‘at risk’ versus ‘it’s good age’, but have a number of 3rd leaf trees where the top of the scion is still not entirely healed over… I suspect something like a side graft.
I sense the type of graft will ultimately affect the strength of the union, but perhaps that wanes with age, esp. beyond 5 years.
We saw, some pretty heinous wind here this weekend… gusts in the area up to the 90’s. Sounds like once mature, there is not a strength difference for most situations unless influenced like you mention, but I wonder about our more severe events. 2 years ago, I lost (to wind) half of a 50’ pine, which had a co-dominant leader from about 15’ up… similar situation with half of a 40’ pine landing on the house a few weeks ago after 2’ of heavy snow. Of course, those are known weak situations, but my point is that wind and snow load can be the real deal here.
Tell me more about that… I don’t think I’ve ever seen those deep versions mentioned. I would say every few years, we have some winds in the 75-90 mph range.
This is from old village men’s and travelling grafters’ (used to be a thing in CE pre WW2) tales comparing grafting to joinery (in the fashion of stability of different approaches of attaching a leg to a chair - would you rock in one if the back legs were glued from the back side?) and some old Czech and Slovak literature where types of grafts were discussed in terms of weather conditions. Bottom line being wedge and W&T (almost forming a Z-like double wedge) are more stable. Side grafts were discouraged
& SG on the side towards which the wind blows and most trees in the area are leaning was mentioned almost like asking for it.
Those traveling pomiculturists would graft wild seedlings and maybe see the trees in a few years, some of them in remote locations. So there was no after care expected.
I can’t tell you more, but that rule makes sense. Some grafts will be stronger than others especially in the short run. Short run being a few years. Bark grafts of certain kinds that basically heal mostly on one side will be weak.
With 90 mph winds the best hope is a strong form of support.
This is my first ever bark graft experiment from last year. It is Braeburn apple on M9. It is in one of the less windy spots I have and I grafted on the wind exposed side so as not to rig the experiment to an extreme. The M9 (wheelchair rootstock) was pushing it enough, but I used that because it is popular and I wanted to see, how it recovers, anyway.
And here is the other side - I grafted under left flap. I cut off the unattached bark to see the joining. Now, it was a crappy year, as in zone 5 spring and I would have grafted later, had I known… But the rootstock did not even callus.
I was planning on giving it a strong nudge next year, but I don’t think it will be necessary if there is any fruit. I might try it on a vigorously growing seedling, when I find one large enough and free, just to see if I get a better result. But I don’t see myself bark grafting any time soon, unless it is an old tree.
To be honest, I do use side grafts (side+W&T or modified cleft depending on scion width), but only on branches for back-up / scion repository. By the time those bear more than a few kilos, I have grafted them elsewhere and can spare the branches should they come off.in a wind storm.
Sorry for any confusion… that was in reference to what a deep wedge or deep w&T are.
Agreed support is a good thing. Yes, have always struggled to think of bark grafts as becoming strong, when the ratio of branch/rootstock to scion is large. Makes me think a little more about top grafting, and how/if that is the same story.
if the scion is very thin - this has worked even on a Conference pear in a very windy location and that crazy thing grows like magic beans and bears fruit in clusters large enough to break branches at shoulders if we don’t thin it soon enough. I also use vigorous seedling rootstock in windy locations, so the union swells with new tissue and is likely the stronger link in the chain, so to speak.
If the scion is a regular pencil size or slightly thinner, then normal wedge just aligning cambium on one side only. (pushed in so deep it would seem like no wrapping was necessary if it were not for the blasted windy weather )
Thanks, Tana. I had a look at that goat’s foot/inlay graft, and will go look a the rest of the thread. Getting the shape of the cavity on the rootstock to match seems pretty advanced, but I will do some practice.
In my case, the rootstocks are around 6mm and some of my scions scion around 2.5-4mm.
When I was looking up wedge graft, I saw an image looking like this, which would be more simple with the 1/2-width scion inserted only on one side. Would the void left on the rootstock be a problem, provided it was coated? I would think an air gap could cause bigger issues.
My grandparents on one side of the family immigrated to the US from Slovakia, as children.
) and then there is a rule of thumb, that you use deep wedge or deep W&T in an extremely windy location, hence my third question. But if the rootstock is good and you don’t overload the tree in the next season, you should be (generally 
)