I am curious about a sort of potential workaround for the issue of grafting quince and apples together. I know that with standard grafting the graft will almost certainly fail within a few years, if it even takes to begin with. In my case the main reason for any and all grafting I do is to increase total number of varieties while working with my extremely limited growing space.
To get to the point though, would an approach graft be a viable option? More specifically, would it be a reasonable idea to use an approach graft to fuse an apple and quince near the base and just not remove the roots of either one? Would this allow them to grow in such close proximity that they, space wise, would function as one tree with two varieties?
My thinking is based around that it is possible to get a graft to take temporarily between them. (one I did when I was younger of quince onto crab apple is still going at five years!) It seems the two are incredibly close to being able to form a successful graft but that the grafted section's nutrient needs eventually reach a tipping point that the union cannot meet, so perhaps using this method the quince's roots may be able to survive and essentially supplement those requirements and vice versa?
I would just reply to the question that lead me to this site but it hasn't had anything in many years.