Fruit tree pollination can seem a bit mysterious at first but the following notes should help to explain it:
The flowers on a fruit tree need to be pollinated, (receive pollen from a different flower), usually by flying insects, if they are to become fruit.
Some fruit trees are self fertile, i.e. they can pollinate themselves; most however, need pollen from another tree of the same species, but of a different variety. For example, an apple tree, e.g. Discovery, will need pollen from another apple tree, e.g. Cox, to produce fruit. A pear or cherry tree will not pollinate our apple trees. Some apple trees, such as Bramley, are sterile and cannot pollinate another apple tree, they can be pollinated, however.
To ensure you get fruit from both your apple trees you need to introduce a third tree, to pollinate the tree that Bramley cannot. Bramley is said to be a TRIPLOID.
Fruit trees flower at different times, some early in the spring, some later. To ensure you fruit trees pollinate each other they should be flowering at around the same time. This is the essence of the pollination groups. Apple trees in group A will flower earlier than those in group B, and group C will flower later still. It follows that you would be unwise to choose one tree from group A and one from group C as they will flower at different times and pollination may be poor or non existent.
Plum trees always flower quite early and pollination, and subsequent fruit yield, can be badly effected by a wet and cold March/April. Peach and nectarine trees flower earlier still and the flowers can often be damaged by frost and wind, they may need hand pollinating with a brush as there may not be sufficient insects around at this time of year. If you live in colder districts it pays to plant later flowering trees.
If you can only plant one tree you can plant a self fertile variety, or ensure there are other, similar trees, nearby. Another alternative is to plant a family tree, which has more than one variety grafted onto the same tree.
