There are two types of pollination. Self-pollination occurs when the pollen is transferred from the anther to the stigma on the same flower, from another flower on the same plant, or from a flower on another plant of the same variety. Many plants cannot produce fruit from their own pollen and are considered self-unfruitful. These plants require cross-pollination for fruit set. Cross-pollination is the transfer of pollen from one plant to the flower of a genetically different plant or variety.
Pollination is an important factor when selecting and planting tree and small fruits.
A list of pollination requirements for the various fruits is presented below. Apples are considered self-unfruitful. Most apple varieties will set a small crop with their own pollen. For maximum production, however, plant at least two different varieties with overlapping bloom periods to insure cross-pollination and fruit set. Apple cultivars can be classified as early, mid, and late season blooming.