Apples don't all blossom at the same time, and many need pollen from another variety to set well. When planning your orchard it's worth thinking about this. One of the most useful apple books (published in conjunction with Brogdale horticultural trust, which housed the English national apple collection) , 'Apples, a Field Guide' by Michael Clark ISBN 1-873580-57-6 which I have beside me as I type, has a numbered 'flowering group' 1-5 with each apple description, which is a great help. If you have 5 or more different apple varieties, have e very fertile tree like Sunset, or live in a city and your neighbours have apple trees, you are unlikely to have any difficulty with pollination. But if you plant just 2 apples, and they are in flowering groups 1 and 5, chances are their blossom will not be out together so they may fail to cross-pollinate. It is better to choose apples which will flower at the same time-they need not be in the same groups, adjacent groups (eg 2 snd 3) is fine. Also remember some aples, Bramley for example, are triploids and do not pollinate other varieties. I can' put up a full list of apples which are self fertile or completely sterile without a pollinator, look it up or ask your supplier. Michael Clark''s book mentioned above is excellent. Some trees are biennial, flowering (and therefore fruiting) only every other year. This is obviously a demerit. Some of the very best cider apples (for example, Tremlett's Bitter) are biennial, but are so useful in a ...