Cross-Pollination for Apple Trees

An apple tree produces fruit when planted near another variety of the same fruit.

Cross-pollination is the transfer of pollen from one apple tree to another apple variety. Without pollination, apple trees will not bear fruit. Flowering crab apple trees are popular for cross-pollination because they require little care and they bloom for longer periods of time than regular apple varieties. Although some apple varieties claim to be self-pollinators, when cross-pollinated these varieties tend to be more fruitful.

The Importance of Honeybees

An apple begins as a flower on an apple tree. Visits from bees ensure that the flower eventually becomes an apple. For this to happen, the pollen of one apple tree needs to mix with the pollen of a different apple tree. This occurs in two ways. As the bee flies from the flower on one tree to a flower on another, the pollen stuck to its body hair transfers to other blossoms it visits. Other bees also help to pollinate a tree. When a bee returns to its hive, it habitually rubs against other bees, exchanging pollen with its hive mates. When the bee visits its favorite apple tree, it transfers the pollen on its body to blossoms on the tree.

Effective and Ineffective Varieties

Some apple trees are very successful pollinators, and others are not able to take part in pollinating other trees. Good pollinators are crab apple varieties such as Dolgo, Whitney, Manchurian, Wickson and Snowdrift. The apple varieties that produce sterile pollen and are not equipped to pollinate are Baldwin, King, Gravenstein, Mutsu, Jonagold, Staymen, Rhode Island greening and Winesap.

Self-pollinating Varieties

Some people do not have room for the trees necessary to cross-pollinate. Those who can fit only one tree on their property can still have an apple crop. Self-pollinating varieties are available that can pollinate themselves. These varieties include Golden Delicious, Braeburn, Granny Smith and Scrumptious. Owners of only one tree can ensure pollination by hanging a bucket of water filled with branches of open, fresh blossoms of a different apple variety on the tree.

Role of the King Blossom

On an apple tree, the king blossom is the largest and first one to open. For the best fruit crop, the king blossom needs pollination. It is important that the bloom periods of the pollinating tree and the king blossom overlap. The trees also need to be within 100 feet of one another to ensure adequate pollination.

References

• Washington State University; Pollination of Fruit Trees
• University of Missouri; Pollinating Fruit Crops
• Colorado State University; Pollination of Tree Fruits
• Michigan State University; When Fruit Trees Fail to Bear
• "Mother Earth News"; Self-Pollinating Apple Trees: An Easy Way to Grow Apples; Michelle Martin; May 26, 2010
• University of Arizona; Information Sheet 10