Should I graft/top work these unknown mangos?

[cgbills]

When we moved into our house in September, there were three unknown potted mango trees that were left and one unknown mango tree in the ground. Since we had the space and I did not want these potted mangos to die, I went ahead and put the three unknown mangos in the ground near the previously planted unknown mango. All of them have been doing pretty well and kicking out a lot of new growth. One in particular is doing VERY well with a very nice bushy structure and many terminal ends; however, I am debating top working these into varieties that I know and want. Here are my thoughts.

First, I do not think two of these trees are grafted. As you can see from the pictures, two of the trees have growth tied off. I thought this could be growth from the root stock popping out, or maybe they are shoots from a poly embryonic seed they tried to stop. So do you think those tie offs are from grafting or from poly embryonic shoots? I know they were trying to do some work with trees and possibly selling as a nursery, so could they be root stock they were growing? Even if it is a graft, I do not know if it is the root stock or graft that “won” and which is growing

Second, the other two trees have a nice V structure, but I cannot tell if these are grafts either. These second two are the ones that are doing the best, but idk if they are grafted or from seed. Do you think these V shaped trees are double grafts or just grown from seed?

My main concern with just letting these 4 trees go is I will be waiting 7-10 year to get fruit if they are not grafted. It maybe cool to just let them go and see what I get, as I have several other trees; however, it would be a long time to let them grow, possibly fruit, then have to wait for new grafts to produce if the original fruit is bad. The whole thing ultimately is not a huge issue as I have several other trees, but I am trying to plan things out. The main corse of action I am leaning towards is grafting/top working the two trees that have the shoots tied off and let the other two V shaped bushy trees go. Thoughts?

[Galatians522]

None of those appear grafted to me. Actually, my guess is that they are rootstock trees that weren't grafted because they aren't configured for easy grafting. That "V" may come back to haunt you. You can see where other people have posted about similar tree shapes that split in half years down the line.

[cgbills]

Is it possible to cut a few inches under the V and graft to the trunk there? To be honest there is only one of the 4 trees I would be interested in letting grow to see what it does. The one V trunk tree is growing really well and I kind of want to see what it does. If the others are not grafted, could I just make the initial cut below the V/collateral growth, then graft on there? Would grafting too low be a problem?

[Oolie]

I see at least one failed graft, looks like two.

The crotch angles on the "v" trees is too narrow, less than 60 degrees, when the trees are larger they will split there. Better to lose the extra growth now when damage will be small. For each of those, pick a winner and remove the other side, then plant so the winner faces mostly up. Since they are in-ground already, you can put a stake in on the side you cut away and bend the tree and secure it to the stake until the tree starts growing in the right direction.

You can graft low and it's not much of an issue, but I usually head back trees pretty hard when grafting. On trees the size of yours, you might as well head back the top a bit and graft higher, and let the scar lower down get "healed over".

If you want to gamble on seedling genetics, crush some freshly flushed leaves and smell the sap.
That will give you a general idea of how the fruit will taste. If you don't like it, just graft to something you want. I know if I found sap smelling like Alphose I would let it try to fruit, but taste is subjective, I know others who would graft it right away if it had that smell.

[cgbills]

This first question maybe a little unrelated to my first post, but I feel it is worth asking. Don’t we want to encourage more branching, and don’t you want several strong branches to make up the central structure of the tree? Are you saying there is an issue here because these V’s are low and technically are the trunk, forming a co-dominant union? If that is the case, How far above the ground is it ok to allow such a V shape and or branching? At what point does it stop being co-dominant and just becomes branching?

Regarding choosing a winner and pruning the loser side. How close to the trunk should I cut the losing side? Should I try to cut the losing side as close to the trunk as possible to make it easier to heal over? Also should I put anything on the spot to promote healing and ward off infection? Or will it scab over and heal on its own?

Regarding the head back pruning and grafting. Are you recommending that I prune everything and go up to the first branching or first green wood, whichever comes first, and graft there? The first branching points are about 1.5 and 2 feet up respectively. If I prune it below the first branching and graft there, what type of graft should I use? Also could I graft 2 or 3 scions that far up to star forming the branches of the tree? Finally should I wrap anything showing green below the graft to help keep the rootstock from kicking out new growth?

Thanks for the help

[Galatians522]

CG, the grafting questions are above my pay grade since I am not an expert grafter. But I'll answer regarding the tree shape. The trouble with the "V" is the angle not the branching itself. Some day half of the entire fruit load for the tree plus all the weight of half the canopy will be pulling on each half of that "V". That is a lot of stress and tension. I've seen many lychee trees in our grove which had that shape break in half over the years and others have posted the same for mango. If the branch is at a wider angle (closer to 90 instead of 45), the weight pulls down instead of out (if you follow me) and its not typically an issue. Its possible that the tree will never get a high enough fruit load to cause that to happen, but its definitely a risk.

[cgbills]

CG, the grafting questions are above my pay grade since I am not an expert grafter. But I'll answer regarding the tree shape. The trouble with the "V" is the angle not the branching itself. Some day half of the entire fruit load for the tree plus all the weight of half the canopy will be pulling on each half of that "V". That is a lot of stress and tension. I've seen many lychee trees in our grove which had that shape break in half over the years and others have posted the same for mango. If the branch is at a wider angle (closer to 90 instead of 45), the weight pulls down instead of out (if you follow me) and its not typically an issue. Its possible that the tree will never get a high enough fruit load to cause that to happen, but its definitely a risk.

Ok so the main issue is how much load each of the first main branches is carrying, not so much how far down the trunk it is. With that then, is three main branches from the trunk considered enough to bear the weight of the tree and fruit? It probably depends on how much fruit we are talking about, but several of my trees’ first splits are into three main branches.

I guess I will go ahead and deal with these V shapes. I have these two and a young M4 in the back that need straightened out.

Also, on the question of grafting. I have seen a video from Dr. Campbell where top worked a tree. He did so by cutting it to a stump and grafting 3 scions directly to the stump just under the bark. Admittedly he said it was kind of a drastic form of grafting. Is this type of grafting less likely to take vs grafting further up into more green wood?

[Galatians522]

3 might be ok. 4 would be better. But you can help things out if you spread the branches while they are young. That strengthens the crotch.

I'll defer to one of the grafting experts for the top work question.