@mamuang - you are right… I need to hear from someone local like @thecityman, or other TN folks…
I went back and read several post here talking about Shiro and pollinators, and it seems there is no real consensus… It seems what works for one person in one location does not work for others in other locations… and even the weather (little warmer or cooler spring) can change which other tree actually pollinates with Shiro.
Below is some info I found online…
Below from Goog.
“Methley” is a low-chill-requirement plum tree with hardy blossoms, making it compatible with Shiro plum in mild-winter locations. “Starking Delicious” is a registered cultivar that shares the same bloom period and cultural requirements as Shiro plum, making this tree a suitable pollinator for Shiro plum.
Stark recommends… Ozark Premier, Burbank Elephant Heart, Bubblegum, Alderman
Raintree recommends… Early Golden Asian, Emerald Beaut Asian, Golden Nectar Asian
Burnt Ridge says Shiro + Methley on a pollination chart.
For the most part — seems to be no real consensus on the best pollinator for Shiro.
I did find a youtube last night (link provided) and this guy has two Ozark Premier and a Shiro.
His Ozark Premier trees are well into blooming, and his Shiro has just a few early blooms on it. It looked to me like his Shiro had just a few early blooms on it, but the Ozark Premier was a little ahead of the Shiro.
So at least in his location (and not real sure where that was) and in that year, Ozark Premier and Shiro were blooming at the same time.
I found another guy that has a Shiro, Sweet Treat Pluerry and Weeping Santa Rosa and his Shiro was… 4-5 years old and loaded with fruit. I am not sure if those were the only varieties he had, those were the only ones he mentioned. He shows all 3 well, does a taste test, etc…
I think ideally for me, I wouild want a pollinator for Shiro, that is known to be as late frost hardy as Shiro (if possible)…
I grew two varieties of J Plums for 13 and 14 years… don’t remember the variety name, but they bloomed in Feb… one started blooming Mid Feb, and the other about a 5-6 days after it.
In 13, 14 years we got one good crop off them, and a couple small crops.
I had no pest or disease issues with them… just could not get them to crop often enough.
@steveb4 - glad to hear you finally have some stuff ripening up there…
From an old movie… Jerimiah Johnston… winter sure stays long this far north 
@blueberry - I picked a pile of rabbiteye berries last night tiffblue, brightwell, powderblue, but they are starting to slow down here now. the end is coming.
PS… on Blueberry fertilization… I fertilized mine early (before bloom)… and now once all fruit is harvested… Fertilize again ? That is what I have been doing… Hollytone, and some bloodmeal, epson salt. Seems right to me, but let me know how you do that please.
Thanks
TNHunter