Pollinizers

Pollinizers are plants used to provide pollen to another plant to enable fertilization and fruit set, especially in fruit-tree cultivation. The term is most commonly applied to orchards where the main cultivar is self-incompatible or yields better with cross-pollination.

A pollinizer is selected to bloom in close time with the crop cultivar and to be compatible at the pollen level. Selection factors include overlapping flowering period, cross-compatibility, pollen production, tree vigor, and suitability to local climate and soil. Pollen compatibility is genetic and may involve interspecific or intervarietal crosses within the same species.

In practice, pollinizers are planted among main trees or in nearby blocks so that pollinators such as bees can transfer pollen efficiently. The pollinizer may be a different cultivar, or a crabapple or quince in some fruit crops. While not always labeled as productive fruit, pollinizers support greater fruit set and can influence size and uniformity.

Common examples include using crabapple or quince trees to pollinize apples, and interplanting compatible pear cultivars in pear orchards. For cherries and plums, several cultivars are chosen to bloom together to promote cross-pollination by insects.

Management considerations include arranging plantings to maximize pollinator access, monitoring bloom overlap, and pruning and maintenance of pollinizer trees to maintain pollen supply and orchard structure. Environmental conditions affect pollination success.

See also: Pollination, Cross-pollination, Self-incompatibility.