Q.apple trees blooms, fruit only on one.
I have two Granny Smith apple trees that both bloom profusely, planted about 3 or 4 years ago. One way smaller than the other one but that’s the one that produces fruit. Majority of suggestions are than two different varieties need to be planted for cross pollination success, but do the large commercial orchards do this? Seems unlikely to me. Thank you. Fran
"Granny Smith" apple trees produce a better crop if cross-pollinated with a suitable apple tree variety.
To cross-pollinate apple tree varieties, you have to plant a compatible tree. "Snowdrift" crabapple is a useful pollenizer for apple trees that bloom mid- to late-season, like "Granny Smith." "Golden Delicious" is another smart choice because of its heavy pollen production. When choosing trees for cross-pollination, it is important that you choose apple varieties with overlapping bloom times because very early and very late varieties cannot pollinate each other.
https://www.gardeningknowhow.com/edible/fruits/apples/self-fruiting-apple-trees.htm