How to Cross-pollinate Nanking Cherry Trees

If you live in a cold climate and are looking for a good, low-maintenance cherry for pies and cobblers, consider the Nanking Cherry (Prunus tomentosa). It is a tough deciduous shrub, hardy in U.S. Department of Agriculture plant hardiness zones 3 through 6, and makes great edible hedge. They are tolerant of drought and high winds and grow quickly to 10 feet tall and wide, but can easily be maintained at a lower height. Nanking cherries are not self-fertile, but require the pollen of another plant for good fruit production.

White clover seed

Artist's paint brush

Plant two or more Nanking cherries to ensure there is a compatible pollen source for each one. Any two Nanking cherries that are flowering at the same time will provide pollen for each other. Plant them a maximum of 100 feet apart, but ideally they should be planted together in same hedge row for best fruit production.

Establish nectar sources for pollinating insects, especially bees. Nanking cherries flower for a brief period in early spring and must be pollinated during this period. Plant other nectar sources that will bring the bees to your garden in large numbers so they are there when the cherry flowers open. White clover (Trifolium spp.) is an excellent example of an early-flowering plant that attracts large numbers of bees and is easily grown from seed. This is the same clover that is commonly found in lawns and is hardy in USDA zones 3 to 10.

Create habitat for pollinating insects. If conditions are cold, wet or windy while your Nanking cherries are flowering, pollination is less likely to occur because bees and other pollinators are inactive in inclement weather. Planting in a warm, sheltered area, such as the south side of a house or behind a windbreak of some sort fosters the conditions for pollination to occur. Plus, dense shrubbery nearby gives a place for pollinators to take cover in wind or rain, so they can return quickly to their work when the weather clears.

Transfer the pollen directly, if all else fails. This is mush easier than it sounds -- simply use a small artist's brush to dab pollen from the flowers of one Nanking cherry onto the flowers of another. The yellow pollen grains are found on the ends of the long stamens inside cherry flowers. They need to be transferred to the female stigma in each flower. The stigma is a knobby protrusion found in the center of the cherry flower around which the stamens are clustered. The stigma is bright green and shiny when it is receptive to pollen.

If the pollen is brown, rather than yellow, it is no longer viable. Cross-pollination should be completed in the first 24 hours after the flowers open to be successful.

Avoid the excessive use of insecticides around Nanking cherries. They will kill pollinating insects along with the pests for which they are intended.