What is the root stock for commercial plum trees?

Being on an extremely low, to no-budget-at-all to start my food forest, I managed an end-of-season Santa Rosa Plum tree at Big Lots. It was almost free. Well, between it being poorly cared for at the store, and the city-dwelling deer I didn't know we had, the tree got cut back below the graft. It is doing really well now. I built a wattle around it of mulberry branches. But I am wondering what, if anything, am I likely to get? I have no idea what the base stock of my tree is likely to be. I am hoping there are some orchard folks who can enlighten me. Thanks.

Dave Wilson has a list of common rootstocks for peaches, plums and hybrids.

well theres no way to know for sure because that particular nursery couldve used something uncommon...but most of the time people use a type of prunus cerasifera as a rootstock.

prunus cerasifera is also called myrobalan plum.

this is a wild cherry plum, a little bit more tart and less sweet than a cultivated plum. plus they are small, cherry plums. personally i like them, but i may have a more adventurous palette than yours.

if you still have the tag you could look up the nursery its from, and a lot of have websites or you can find out what they use....

Fedco uses Prunus Americana, and so do I. It works really well.