Which Apple Varieties Are Blooming Now? Early Bloom Season. 12 Apr 24.

 Apples require cross pollination.  Or the vast majority of them do.  Apple varieties need to bloom together, to cross pollinate.

Varieties in bloom now can pollinate each other.  The exception is that triploid varieties can receive pollen from the more usual diploids,  but triploid pollen is not viable.  So it usually takes two diploids, so they can pollinate each other as well as the triploid. 

The overwhelming majority of apples are diploid.  I mention it here because Gravenstein is triploid.

Blooming heavily now -

Gravenstein.

Redlove Calypso.

Redlove Era.

SummerRed

Zestar.  This is sort of a "Wow" right now.

Columnar Supposedly Tasty Red, but it isn't (Maybe Blushing Delight?)

Also North Pole.