Pollination groups

There are four to seven pollination groups in apples depending on climate :

Group A – Early flowering, May 1 to 3 in England (Gravenstein, Red Astrachan)
Group B – May 4 to 7 (Idared, McIntosh)
Group C – Mid-season flowering, May 8 to 11 (Granny Smith, Cox's Orange Pippin)
Group D – Mid/Late season flowering, May 12 to 15 (Golden Delicious, Calville Blanc d'Hiver).
Group E – Late flowering, May 16 to 18 (Braeburn, Reinette d'Orléans)
Group F – May 19 to 23 (Suntan)
Group G – May 24 to 28 (Court Pendu Plat)
One cultivar can be pollinized by a compatible cultivar from the same group or close (A with A or A with B but not A with C or D). Late groups are better to avoid frost in cold areas.