The Honeycrisp apple, a crisp and sweet variety developed by the University of Minnesota, has become a favorite for both commercial growers and home gardeners. While this tree is hardy and produces highly sought-after fruit, it cannot bear a harvest on its own. The straightforward answer to whether a Honeycrisp apple tree needs a pollinator is a clear yes. To ensure fruit production, the Honeycrisp requires cross-pollination from a compatible variety of apple or crabapple.
The Biological Necessity for Cross-Pollination
The need for a partner tree stems from the genetic makeup of the Honeycrisp, which, like most cultivated apple varieties, exhibits self-unfruitfulness, or self-incompatibility. This means a flower cannot be successfully fertilized by its own pollen, or even by pollen from another Honeycrisp tree.
Apple trees possess a genetic barrier known as the S-locus, which prevents the pollen tube from growing down the flower’s style if the pollen grain shares the same S-alleles as the flower. This system encourages genetic diversity, but it makes having a second, genetically distinct tree necessary for fruit set. For a Honeycrisp flower to develop into an apple, its ovules must receive viable pollen from a different, compatible variety.
Identifying Compatible Pollinizer Varieties
Selecting the right pollinizer is a matter of ensuring the two trees are genetically compatible and that their bloom times overlap significantly. The Honeycrisp apple tree is generally considered a mid- to late-season bloomer, so the pollinator variety must flower during the same period to allow for successful pollen transfer.
Mid-season blooming apple varieties that work well include:
- Gala
- Fuji
- Golden Delicious
- McIntosh
- Liberty
- Granny Smith
Crabapple trees are also excellent choices because they produce abundant, long-lasting blossoms and are highly compatible with most domestic apples.
The ploidy status of the pollinizer tree is important. Honeycrisp is a diploid variety, meaning it produces viable pollen that can fertilize other trees. The chosen pollinizer must also be diploid; triploid varieties, such as ‘Jonagold’ or ‘Stayman Winesap’, have three sets of chromosomes and produce non-viable pollen, making them ineffective as pollinizers for any other apple tree.
Practical Methods for Ensuring Successful Pollination
The most straightforward way to ensure cross-pollination is to plant a compatible pollinizer variety within 30 to 50 feet of the Honeycrisp tree. This proximity ensures that pollinating insects, primarily honey bees and native mason bees, can easily move between the two trees to transfer pollen. Bees are responsible for nearly all successful cross-pollination, so encouraging their activity by avoiding insecticides during bloom is highly recommended.
For gardeners with limited space who cannot accommodate a second full-sized tree, several practical solutions exist. One effective technique is to graft a scion, or small branch, of a compatible pollinizer variety directly onto one of the branches of the Honeycrisp tree. This creates a single tree that carries both the fruit-producing Honeycrisp wood and the necessary pollen-producing pollinizer wood.
Another temporary solution is to use “pollinizer bouquets” during the bloom period. This involves placing cut branches from a flowering crabapple or compatible apple variety in a bucket of water and setting the container near the Honeycrisp tree. Bees visiting the cut blossoms will inadvertently pick up the foreign pollen and carry it to the Honeycrisp flowers, facilitating cross-pollination and fruit set.