Pollination and compatibility

Most apples and pears are self-sterile. They need pollen from a different variety to set fruit, and that variety must flower at the same time. Pollination groups run from 1 (very early) to 7 (very late); you need trees within one group of each other. A group 3 apple like Cox will pollinate a group 2 or group 4 tree, but not a group 6.

Triploid varieties complicate this. Bramley, Jonagold, Ribston Pippin and Blenheim Orange are triploids — they produce sterile pollen and cannot pollinate anything, including themselves. If you plant a triploid, you need two other compatible varieties in the garden to pollinate each other and the triploid. This is why Bramley is a poor choice for a single-tree garden unless a neighbour has apples within 20 metres.

Pears follow the same logic but are fussier. Conference is partially self-fertile and will set some fruit alone, but crops far better with a pollinator like Concorde or Doyenné du Comice. Williams' Bon Chrétien is incompatible with Conference and Seckel — check the nurseryman's pollination chart before buying.

If you only have space for one tree, choose a family tree. These are single rootstocks grafted with three or four compatible varieties that flower together. They look peculiar but fruit reliably and solve the pollination problem in a 2-metre circle.