Top left photo shows one of my blueberries that blooms very early. In the past it always bloomed ahead of everybody else, and only set (delicious large) fruits very sparsely, which then needed to be jealously guarded from predation by catbirds and robins. ...we only ever got 1/2 a dozen if we were lucky
... It was one of the first blueberry bushes I planted, and I've lost the tag, though it may be Patriot.
Two years ago, I noticed that the cultivar called Top Hat, which I had planted in a patio planter the year before that had started to bloom heavily for the first time. But it barely set any fruits -- I guess they aren't as "Self-fertile" as advertised. I moved another one that I'd planted elsewhere into the same planter.
This year, I realized that Top Hat and the unknown earliest bloomer were blooming at the same time. AH HA!!! -- I trundled the planter to the blueberry patch, right outside the fence to to the blooming cultivar. You can see the result in the top left and bottom left photos.
Top center photo is a wild NJ low bush blueberry. I has bloomed in synch with the Elizabeth cultivar pictured on the bottom right.
And center bottom and last top- right photos show a weird blossom damage that puzzled me at first. I even cautiously peered inside the blossoms to see what had forced its way in. But then I realized -- these are the work of bumble bees and carpenter bees -- very busy pollinating the blue berries most of the time. They can't get inside the flowers so they tear them open at the base.