When mowing last week I brushed a well established (14 years) A. rufinerve 'Albolimbatum' (sometimes called 'Hatsu yaki now) with the grass box on the tractor. Imaging my horror when upon turning around and seeing the entire tree lying, broken, on the ground... It was really a very light touch, but must have snagged a branch an twisted a little. This tree came from the French nursery Adeline, since closed as M. Adeline retired. He liked to do low in-ground grafting, and I had never examined the graft on the tree as it was already below ground in the pot when I received it (a 3 litre pot IIRC). However on examination I observed that the tree had callused out above the graft, and in fact the bark ran in on one side to a relatively small join with the stock. The entire thing was structurally very weak, it probably would have come down eventually in a wind storm. And of course if it was much larger, coming down could have cause considerable damage to the garden. So although I thought the tree completely established it was really in danger because of the graft issue. Perhaps eventually it would have put down additional roots above the graft, but that's the only thing I can see that would have saved it in the long term. It will be interesting to see whether the rootstock when it pushes up is a rufinerve or a davidii. Apparently it is better to use davidii rootstock for section macrantha as it is stronger. Still very sad to lose it. It was a beautiful tree and admirable in all seasons. Luckily it isn't my only 'Albolimbatum', the other one is just a little smaller.
That will be very interesting to see. My own (non-scientific) thoughts on the subject are that a graft on a different species will more likely have these graft failure issues down the road than a graft on the same species would.
