I grow them for a while...as far as I know they grow upright but soon they weep. Your damage will recover soon with new shoots, you'll see at the end of the season they
look just fine.
One thing I'm trying to grow upright is by top graft cherry plum onto plum trees. I want to to the same with the sand cherry...need to find a host.
I'm doing it the other way too, grafting plums onto cherry plum
and sand cherry...resulting in a dwarfing low tree.

Hi Konrad!
Most of the seedlings I have tried over the years tend to want to grow as a shrub (naturally)but I am trying to train some up into a more upright style. The one I have seems to like this so I will prune off the suckers but one and try again. The row of cherry plum seedlings has several of them that seem to want to grow upright rather than bush like so we will see how that goes.

I have not gotten into trying grafting or budding much as I tend to be a seedling grower. Rootstock is always a challenge for the plum family. My friends over at Little Tree Nursery in Martensville, SK use Sand Cherry for all their plums as far as I know. I have never had good success with plants which I bought on Sand Cherry rootstock. Probably I did not plant them deep enough. I have been told by a friend at the Hort Department at the U of Sask that they are finding that cuttings taken very low on the plant will root - ie plums, apples etc. I have not really tried this but it would be worth it. I picked up some Ptitsin #3 and #5 cuttings from them a week ago so will plant them out soon.