How Far Apart Should Apple Trees Be to Cross-Pollinate?

For an apple blossom to mature into a fruit, cross-pollination must occur.

Except for a few varieties, apple trees must receive pollen from a different variety of apple tree to set fruit, and even self-fruitful varieties will produce a larger yield if cross-pollinated. To have a productive home orchard, you must consider pollination, including the spacing of trees able to pollinate each other.

Tree Spacing

The closer you space two apple trees, the more likely that honeybees will transfer pollen from one tree to the other. For a home orchard, your tree will receive adequate pollination from a compatible apple tree located within 100 feet of it. For optimal results, you should space the trees closer together. Locate semi-dwarf trees 50 feet apart and dwarf apple trees 20 feet apart.

Suitable Pollinators

You also need to consider if the two trees you plan to cross-pollinate each other are compatible pollinizers. Blossoms should be open on both trees at the same time, so an early-blooming tree like the Manchurian crabapple might not provide the best source of cross-pollination for a late-blooming tree like Rome, because the trees will have, at most, a few days of overlapping bloom.

Crabapple trees are suitable pollinizers for orchard trees, and because these are popular ornamental trees, you may already have one nearby in the neighborhood. If you decide to plant two varieties of apple, avoid Winesap, Stayman, Mutsu and Jonagold, which produce sterile pollen and cannot cross-pollinate other varieties. Granny Smith and Rome apples are not suitable pollinizers for some apple varieties, so check compatibility of your trees before planting.

Other Pollination Considerations

Honeybees act as the primary pollinators for apple trees. While commercial orchards will often bring in beehives to ensure adequate pollination, wild bees should meet the needs of home fruit plantings, if you space your trees correctly and choose compatible pollinizers. A single bee can pollinate 5,000 flowers in a day. However, if bees are scarce in your area, mowing dandelions and other flowering weeds near your trees will remove a tempting alternative food source.

Pollinator Alternatives

Homeowners often lack the space to plant two apple trees. If you can't plant a single tree or discover that a nearby tree is too far away to ensure good fruit set, you have other options available to you. Cut a bouquet of branches from a compatible pollinizer tree, place it in a bucket of water and hang it from the branches of your tree. You can also graft branches from a compatible variety into your existing apple tree.

References

• University of Missouri Extension; Pollinating Fruit Crops; Michele R. Warmund; November 2002
• Colorado State University Extension; Pollination of Tree Fruits; A. Gaus, et al.; October 2009