Here’s my contribution. It’s a work in progress. Dax
Compatibility Among Peach or Nectarine/Plum(s)/Apricots/Pluots/Aprium/Pluerry: compiled notes in addition to (2) reference charts (see beneath.)
European to Asian plum = no
Asian to European is (most) will be successful. Figure that out. Additionally a (CRFG publication: California Rare Fruit Growers) states that the majority of members report incompatibility. I think it should be noted that other than the inland of California (“northern” Cali. about the middle of the state East to West, hilly mountainous country.) See chart… “inland” is referenced for several rootstock & scion combinations… the rest of the country should not have incompatibility problems. Here in IL I’ve grafted Asian plum to European most successfully.
American plum (Prunus americana) accepts: Asian plum; European plum to a degree (beware of delayed incompatibility symptoms discussed below & what to look for); Peach/Nectarine; Pluot aka Plumcot; Pluerry; Aprium; Apricot is 100% incompatible but hybrid plums are recommended to be grafted to American plum. I’m going to leap and say Aprium will graft successfully but also recommend to watch for signs of delayed incompatibility.
Japanese plum to Japanese plum or rootstocks: St Julien, Citation, Krymsk 1, Krymsk 86, Prunus americana, & Apricot.
Peach accepts European plums (chart says); pluots; Asian plums; Euro plums; Apricots are hit and miss.
Apricots should accept most all pluots very well; Japanese plums; European plum (Most not compatible.) Pluots make great interstem combinations between the Apricot wood and European plum scions. (See chart)
Raintree Nursery puts all their multi-plum grafts onto peach root.
Old Asian plum trees may have better acceptance to European plums because they are not as vigorous as younger trees. There within lies the possible compatibility when grafting European plums to Asian plums.
Myrobalan (all are seedlings) accept European plums and prunes. There is reported compatibility with apricots but unions may easily fail during early years after and/or later years.
Myrobalan 29-C (clonal rootstock) accepts all plums: Asian or European; all apricots; pluots aka plumcots; aprium; pluerry; peaches/nectarines not accepted on Myro 29C.
An additional reference from Thompson & Morgan shows Peaches, Plums, Apricots, & Nectarines as perfectly compatible to Myrobalan
ALL ROOTSTOCKS should have a smooth union w/ SCIONS but if swelling is observed, that shows a general issue of incompatibility among the two. Additionally, another general principle that should be observed: full-vigor seedling rootstocks on most all accounts will have less incompatibility with scions than dwarf-rootstocks or semi-dwarfing-rootstocks. This will apply across the board among all fruit trees.
