Is this PlumTree on a "Pixy" rootstock?

[GF3]

Hello.
In December 2019 I bought a Plum Tree and an Apple Tree from Chris Bowers. The tree should have been Red Windsor on M26 - it's not Red Windsor it's Red Delecious. And the root stock? I can't tell if it is M26 or not. The plum tree should be "Blue Tit" on a Pixy root stock. This is the first year it has any fruit - 2 plums! If they hang on I may get some idea if I got the correct variety or not. But it's the root stock that has got me wondering. Is it a pixy root stock? I have attched a photo of the tree showing it on 27-7-2021 and today 24-6-2022. It has grown quite a lot in the last 11 months and the trunk has grown a lot thicker. For reference - the tree stake is 2 inches diameter. Would a pixy rootstock grow this quick?

[ameno]

Pixy is still relatively vigorous compared to the dwarfing rootstocks available for apple trees. There are sadly no true dwarfing rootstocks available for plums. That level of growth is not necessarily uncharacteristic of Pixy.

That said, Chris Bowers is a wholly disreputable retailer who will knowingly pass off one type of tree as another (their range of trees and rootstocks, and their prices should be a clue, really. They somehow have a huge range of varieties, all on every available rootstock, all for far cheaper than any of their competitors. It doesn't add up.), so personally I wouldn't trust them on principle, and since the cheapest plum rootstock is St Julian A, I would just assume by default that it's probably that.

Assuming the plum tree does at least turn out to be the variety you wanted, I would still keep it if I were you. You can limit its vigour somewhat simply be not feeding it, and if that;s not enough maybe allow the grass to grow right up to the trunk.

Your apple tree probably genuinely is on M26, though, as that is itself the cheapest rootstock.

[GF3]

Many thanks for your reply.
I've just measured the height of the three tallest branches on the tree and the tips are over 2.8 metres from the ground. It is out growing the apples trees by quite some margin. It has put on a lot of growth this spring. I did given it some Fish Blood and Bone at the start of spring. But given the rate of growth it did not produce a large amount of blossom. And as I said, it has just 2 plums on it. I will probably let the grass grow around it and give it a summer prune. I don't want it to get too tall
Thanks again for the reply.