I was shocked when I saw how many plums I've got this year. Last year was a real bust for plums for me. I had to thin them today, because I knew I was going to have some broken limbs at harvest time. I remember Jerry SHroyer and Ted Swensen would talk about by when you need to thin the apples so the tree can adjust. I don't know when that is for Asian plums. Are you thinning yet?
John S
PDX OR
In that comment about too much water could (depends on you) mean too much moisture from above and interfering with pollen count, quality or content? ..or just a minor mis-understanding on my part?
This year the PNW conditions provided blessings for not just plums but (as seen in the link below) there was bumper crops being produced on the Moorpark seedling which was locally planted at Wintler Park many years prior.
John: I'm not sure everywhere around town got the same high results with plum though. I have kind of weeded my backyard to two kinds of asian plums now. An all in one tree consisting of Shiro and Adara never got well pollinated between each other. It's still difficult to judge what takes responsibility. Is it low quality pollen and lack of bees a leading cause of lower production for me and some of us this year, or not(?). It's also possible I had these cycles of too much production last year but last year was really low as well. Then as far as at least in my asian plums this teaching of on-off every other year (as per swenson et all) can't take on the blame for that.
How did Jafar in the hills do this year with all his hybrid California bred kinds? The reason why I ask is there may be something to learn in selecting for hybrid early flowering plum types that manage well here due to being hybrid in nature. I have even heard of clones that were propagated in different places, in particular clonal hybrids being indifferent from each other. Most recently though, I stumbled on some important inroads of how many hybrids have the innate ability to produce fruit well irregardless of weather conditions. I may post the source of this self promiscuous feature later. Just depends on how high ed this topic goes into. But the just of it is that all perennial plants posses an ancient form of replication that can turn on by environmental or internal epigenetic measures.
I can't get the list I posted and uploaded within to go away and watching it actually distracts the topic or even the idea of what we are being instructed from our predecessors about thinning for balanced crops from year to year. The apricot one is supposed to be there.
The indifference being mentioned in third paragraph is maybe most meaningfully explained by the fact from my earlier days at NAFEX lists online, I have a Shiro (asian) plum for which growers of eastern states that grow plums and also have Shiro, find them to be unreliable in comparison to mine in my backyard.
Regarding Hybrid plums vs Non hybrids:
Methley, Shiro, and Jafar's are all known hybrid pedigrees. Santa Rosa comments by John are interesting, at least to me, because Santa Rosa isn't a hybrid and he said it's not as productive as these known to be hybrid plums.
So my case in point is going to have to come from more than what John states about Santa Rosa from PNW conditions (westward of Cascades), it may come from Jafar who has much more such as Nadia, Splash etc; all of which are chosen hybrids that more than likely were chosen by he himself as capably productive here where it's too much water compared to California like areas. I am now ready to prepare a conversation I had recently in regards to this innate and primative way of reproduction that I feel is involved for the kinds of hybrid plum trees (that I think Jafar at some point got recommended to by others at other forums) because I think this topic is ready for it at this point.
Thanks John ! 
RE: Innate ability in perennial plants:
..The full context of this is meant to stay edited with names not being revealed such as email contact information so I emailed conversations spanning from April 30th to May 3rd just now to John only.
What I like to cite for all forum interest is stated here:
Elvira Hörandl,
Apomixis and the paradox of sex in plants,
Annals of Botany, 2024;,
mcae044,
https://academic.oup.com/aob/a.....ogin=false
I had mixed results of fruit set on my stonefruit. I think its probably related to when it was rainy and dry relative to bloom, plus the proclivities of the varieties.
Beauty and Splash set the most for me. European plums look sparse this year. Nadia seems to have set a balanced, slightly light crop that probably won't need thinning. Shiro set surprisingly little. Flavor Grenade moderate to high. Hollywood, sparse to moderate.
Pictured are Beauty and Hollywood:
Fantastic !! 
I am especially happy to hear about your consistent production from two of those cultivars shown to me on the multigrafted all-in-one "hybrid". So if Splash and Flavor Grenade are the most reliably promiscuous cultivars on that tree then I can tell you that I experienced no pollen being produced that day two months ago when I got home. So I had nothing to breed with. So if others are not interested in getting in front of me for the seed then I sure wouldn't mind having them. But I will remind you of that question in the future as I concentrate trying to remember everywhere I need to harvest my crosses from cherry trees. Amazingly had success crossing Gisela-6 triploid cherry pollen to other cherry species for cherry rootstock production.
I think I've miscalculated. Looks can be deceiving on these small trees when the fruit are still small.
Beauty is way over-set, there might be 14 fruit in 4 inches where shouldn't keep more than 2. The Hollywood may be close to optimal, I'm guessing 70%. I pinched off fruit from my Splash pluot until my back and patience were worn out and it just made a dent.
Shiro broke a limb completely off and cracked another one so it is dangling. Many limbs are resting on the ground and it is very difficult to maneuver through the paths. I'm glad (temporarily) that I'm not tall or it would be worse. Of course, it would help me in basketball, but that's unrelated. Methley plum is ripe now and it hasn't broken yet, so I'm appreciative of that Hollywood is leaning way over too.
John S
PDX OR
Idyllwild
jafar
Marsha H
Viron
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