You need to find pure Japanese plums or pure American or Canadian plums as pollinators. Once they have been hybridized they become unreliable pollinators and nobody really knows for sure because many factors like temperature or lack of pollinators were present etc....

i know toka is a mix between a plumcot and a Native American or Canadian plum and it has definitely increased my plum pollination in my yard with plums that are well known to be stubborn pollinators. You don't really want to plant a native plum but perhaps graft a bunch of branches onto your trees as the fruit will be bad tasting. This all being said I am sure there is many varieties of hybrids that pollinate just fine but good luck finding reliable information on this because it doesn't exist.

i have one pure bred Chinese plum called the ptitsen 5 it pollinates other trees very well and makes ok fruit to. I can bet the toka and ptitsen 5 combination of pollen with a few branches of native plums randomly grafted is why my trees produce now.

getting your pollinators in line and established is much needed for growing plums .sometimes just one combination won't be enough. If you can plant 3-4 or graft

I think chickasaw plums are super tasty (and bullet proof to grow) though I admit they may be the exception as generally I've heard natives are not as nice for fresh eating.

Does anyone know the pollinators for Brook Gold plums? I.'m in V ancouver area.

It's a matter of semantics and some will think I'm being a snob, but words mean things, and this is a forum intended for discussion, and yes, education.

Your question should actually be 'which plums are superior pollenizers?'... sources of pollen.

Pollinators are the insects, etc. that carry pollen from plant to plant, accomplishing the act of pollenation.

Why not Satsuma instead of Superior. Satsuma is tasty but on a small size. People often mention that Superior's skin is sour.

Plums that bloom at the sme time or overlap would be able to cross pollinate one another. Many plums are self fertile but not Satsuma.

In my yard Elephant heart bloom at the same time as Superior so I assume they cross pollinate. I have grafted a few varieties on my plum trees. They all seem to bloom about the same time.

You may want to learn how to graft. Grafting plum is easy. Then, you don't need to worry about cross polkination. Check out Bob Purvis nursery. He sells many scionwoods of plum and other fruit.