Say you planted an apple on a precocious dwarf rootstock like M27 or M9, and then you grew it out normally until fruiting age. If you buried the rootstock afterwards to get the cultivar to develop its own roots, would it maintain its maturity and continue to fruit? or would it revert back in some way?
Has anyone done this? What were the results?
That’s an interesting question. I haven’t tried it intentionally, but I may have inadvertently allowed the scion to root in a few cases using MM111, and I haven’t noted any change in behavior apart from (perhaps) increased vigor. I say “perhaps” because I already prune MM111 back hard to keep it to 8 feet or so, so I might well not notice. For what it’s worth, these trees certainly have not ceased producing as a result of my questionable graft hygiene.
My initial thought would be that in fruiting the tree the vigor could be severely reduced. It should continue to bear fruit, but could take awhile to recover the vigor. Just a guess though. I’ve definitely stunted trees by cropping too heavy too early, and usually require removing a lot of fruit and wood to reinvigorate.
Even if time to full size was increased significantly, if it worked, I could see it being useful in a backyard.
For an orchard, I can picture something like a high density planting where every Nth tree along a row would have its graft buried after maturity. You could time the burying so the eventual standard sized trees would reach full size after the remaining dwarf understory has completed it’s lifespan.
So would that work on trees grafted to dwarfing Province rootstock (short lifespan) and after 10 years of fruiting cover graft to have tree continue on own roots? I plan to graft named loquats onto Province rootstock in order to get fruit in my lifetime. Could graft be buried for heirs’ lifetime?!
I’m just theorising. I’m interested to hear what all the experts here think.
We have a weird orchard that was an experimental trellis orchard put in in the early 60s, I’m pretty sure they are standard rootstock with mixed varieties within the roots. Tiny Golden Delicious trees right next to giant Gravensteins, the spacing is 8 feet and some trees are a pain to prune. Oh and we keep it as a pedestrian orchard haha.
So what I’m saying is that you can just space standards at 8 feet from the get go 
. The close spacing should decorate them somewhat and provide some earlier fruiting and they’ll fruit for 60+ years 
. All kidding aside there’s plenty of work using larger rootstocks at close spacing to devigorate orchards. There are pedestrian cherry orchards on standard rootstocks. And cherries get much larger than apples, we have several seedlings in our tree line that are 60-70 feet tall.
Interesting…what height are they pruned to?
About 8 feet, but I don’t really recommend doing it. They just have too much vigor, so it would require a ton of labor to renew and devigorate them, and labor it hard to come by. However the spots where trees have died and we can train the adjacent trees along the original wire, which grew into the trees before we bought the place, then they actually work really well and have incredible yield. Being able to spread the vigor horizontally works really well.
After the fact espalier - good idea!
Yeah I believe espalier was the original intention because the trunk is at about 6 feet which is where I think the top laterals were. The trunk height is the other issue in renewing the trees because we would have to cut back the entire trunk rather than just scaffolds. They also sucker quite a bit, so I’m pretty terrified of what will happen.
Here’s an interesting article about guyot training in apples and pears as an alternative to high density planting. I believe these are semi dwarf or semi vigorous trees pictured, but they have spacings listed for high vigor trees. This could be another way to produce an early fruiting tree on long lived roots. Perhaps in a home setting, you could establish an x shaped tree as well. Spreading out that much vigor would keep a standard sized tree pretty short and fruit early with the proper early management. It says the high vigor trees have 25 uprights so an x could have 50.
On a side note, I have had standard trained seedling rooted trees flower in 4 years from bench grafts as well. Summer pruning can really help that along.
The Guyot system for apples looks a lot like UFO planting of cherries.
https://www.researchgate.net/figure/Sweet-cherry-trees-being-grown-in-an-upright-fruiting-offshoot-UFO-architecture_fig2_340006678
I take it the consensus on the original question of “would it work” is yes. I suppose in some situations it could shave 5+ years of immaturity off?
I might attempt it with the Reinette d’Amorique on M106 along my property line in a couple of years. That’s about the only spot I could fit a full standard.
I think I just want it to work. I’ll try it with loquat grafted onto Province, covering graft.