I would recommend AU Rubrum, which is the best of the AU series and Santa Rosa, but if you're going to harvest quality fruit you're going to have to spray for plum curculio at least twice during the fruit setting cycle. You'll find that maintaining your trees will require more than visiting your trees once a year. If that is your plan, you're going to be very disappointed in your results.

Thank you so much for your response.

What results other than poor production should I expect without spraying?

It's semantics, but... the pollenator would be the insect - like a bee - that accomplishes the act of pollenation. What you're asking, is actually 'What variety would be an appropriate pollenizer for my AU Roadside plum?"

I had several of the AU series... but... they came from the infamous TyTy Nursery, before I knew better... I never got a single fruit off of them, and I'm not certain that they were even grafted/budded stock, much less the actual named varieties I'd ordered.

I'd certainly include the Chickasaw plum selection, P.angustifolia "Guthrie" as a variety you should also include in your 'want list'.

I would lean towards adding Santa Rosa as a more or less universal pollenizer for Janpanese and hybrid plums since it has a very long bloom season.

What State are you going to be planting these in?

I have au cherry that it believe is actually au rosa (as the flesh is yellow with little to no amber streaks). It is super vigorous and consistently has tons of high quality fruit. I planted au homeside that had nice crop in year 2 so I think is will also be a great tree. Au producer has not produced much but it is own a dwarf rootstock that I believe is affecting it. In southeast zone 8, you are better off with AU series. Also look for bryon series. Both are breed for south and will give you the best results if you can’t maintain them regularly. California plums will die in SE without constant spray program. In year 1&2 the trees will be ok but in spring of year 3&4 you will need to prune heavy and spray with copper. By year 5, you will need to be onsite for spray program. Hope you plan to retire by year 4-5 because any fruit tree will die without constant maintenance as it matures. Also, in years 3-4, you will loose any fruit to plum culio beetle and birds.