It is very challenging to multigraft an avocado tree, no matter how much pinching you do on the vigorous branches, the tree is just too likely to focus energies on the most vigorous branches, or push new sprouts from the base. I have pretty high success rates with late spring and late summer single-variety grafts here in Seattle (but I'm colder than you). But any time I try to build a multigraft tree I'll be lucky to get 50% takes after the initial set of grafts because you cannot properly force the grafts once you have other grafts on the tree that you want to keep. My worst success rates are in winter or early spring, it seems that it's just too cold here and the trees are more likely to abort the grafted stem than form callus.
Is there some reason you want to go the multigraft route? Space constraints or something? I've decided 2 varieties is the most I'll do for outdoor trees, anything more is not worth it other than on my greenhouse trees (space constraints indoors). For 2-variety trees I recommend doing at least 2 grafts of each variety on the same tree and then if you get more than one to take of the same variety you can remove the weaker one(s).
If I want to also test the rootstock, I'll later allow a rootstock branch to grow, once grafts are established. Brad correctly schooled me on not letting rootstock branches remain at the same time as the initial graft, as that greatly increases the chance the graft will be aborted.
Thank you so much for your input, value the advice of everyone here.
The thought was multigraft onto failed in ground trees and have full trees in a much larger space elsewhere. Call it a scion nursery. Many of my scions have failed from ordering sources as they are not fresh and premium / poor bud quality. If you have them available of course you can get some for ultimate take. I also put the varieties I would not want huge trees of mexicola, duke, or overly large trees that take up to much room (to dwarf them). Like you I would love to grow in a greenhouse a multigraft in a pot, but was trying it with unusable trees that did not produce firstly. You are right I did topwork, and single, dual varieties are so much easier to do then multigrafting.
I did think about that. When you graft under the canopy say on suckers, unless they are as CA Hockey said above (2 years old) they are shaded out. So was considering Sun as well. I am sure it favors vigor (Duke) or it's own genetics over scions it does not want. Resource wise I don't know how "Joe Real" does it. Is it he is only adding 1-2 new varieties at a time to not take to many resources. Because if you do more it will favor only some or itself. Pinching seems to do little unless you chop it off to keep the height manageable of the vigorous ones, then you can get sunburn though.
I did as you say graft in the late Spring as here we were 40 degrees differences some night/days, that is nuts. We don't even hit summer till July (Indian Summer) so Spring weather is latter but areas of sunshine in the Winter.
Interesting So Brad is chopping off the branches and only leaving vertical scions. I have seen his top work videos but never with multigraft where you have to keep varieties. It seems to bud and grow around the scion branches even in branch junctions.
