Nadia brought me to see this, as she said the trunk was Prunus serrula, but there were flowers that were not right. Here is the Prunus serrula, Birch Bark Cherry, growing amongst the trees at the end of the north garden (winter garden?). It has tiny petals, maybe twice the length of the sepals. On this tree, flowers seem generally to grow in umbels of two, on somewhat hairy pedicels. Then there is the trunk on the right, admittedly also exfoliating, but not in the same way as the other. Flowers are twice the size, maybe up to 3cm (of course I didn't think to measure them), in corymbs of two or three, no hairs on the pedicels. It has the same profusion of stamens. Is that the Sargent cherry (that I liked) that you thought you got rid of? That was supposed to have flowers in umbels, and long, funnel-shaped calyxes.
The rootstock with hairy flower parts growing from beneath my friend's sweet cherry we talked about before produces similar bark. So this is some other rootstock with reddish, papery bark. It could be anything a grower decided to use, either a named clone selected and sold for rootstock use or a seedling of a species not used much for anything else - and therefore not familiar as a specimen planted for fruit or ornament. Open pollinated seedlings planted and grown on to be grafted upon later could even be spontaneous hybrids.
I had the (seemingly mistaken) idea that it would be unusual, though not unheard of, to graft Birch Bark Cherries.
No, I am sure this is a sucker coming from a root system that consists of a different kind of cherry - whatever general practice may or may not be. Commercial propagators can be like chefs, with their own little ways to get plants reproduced and on the market. Expediency also affects what is done in each particular instance.
But not sweet cherry - the leaves and sepals are wrong for that. It's kind of nice - maybe we should do something with it.
