Today my Minnie Royal cherries are starting to bloom, ahead of their partners. It reminds me of the narrow window for pollination.
In San Diego, we have scattered bloom. For years, my cherries would often fail to crop. Then I started hand pollinating, and I got crops. Of course, some years are easier than others and last year I had tremendous yields without hand pollination.
Pluots have similar challenges in our area, where the cultivars bloom at scattered times. And I have read about a lot of southern California (even N Cal) having frustrations where they seem to have overlap of bloom but poor production.
I recall reading that cherry pollen is viable for less than 48 hours after flower opening. This is something to pay attention to as we try to troubleshoot pollination in areas with scattered bloom. Just thought I would share this in case others are befuddled by low production despite bloom overlap. The flower might be visible for 2 weeks but the pollen might be viable for only 1-2 days.