We picked up a "Blue Satin Plumcot." Prunus Domestica X Armenaica. (RanPro, Tyler, TX) It calls for "a Japanese plum to pollinate." For a Japanese plum, I have many options, correct? Aren't many plums listed as being "Japanese-type?" Also, I can't help but wonder why. I guess it must be that the critical timing of pollination coincides. Anyway, I'm in zone 6B, NE AR.