Bing cherry trees are a favored choice for home orchards, known for their large, sweet, and firm fruit. Each spring, they produce beautiful white blossoms that develop into deep, purplish-red cherries. Successful fruit production from these trees relies on a specific natural process: pollination.
The Importance of Pollination for Bing Cherries
Bing cherry trees are self-sterile, meaning a single Bing tree cannot pollinate itself or other Bing trees to produce fruit. For fruit to develop, pollen from a genetically distinct and compatible cherry variety must be transferred to the Bing blossoms. This process, known as cross-pollination, is essential because sweet cherry varieties like Bing possess a self-incompatibility mechanism. Without a suitable pollinator, a Bing cherry tree will yield little to no fruit. Therefore, planting at least two compatible sweet cherry varieties is necessary to ensure a fruitful harvest.
Selecting the Ideal Pollinator Varieties
Several sweet cherry varieties effectively pollinate Bing cherry trees, provided their bloom times overlap. Recommended options include Stella, Lapins, Van, Black Tartarian, Rainier, and Black Republican. These varieties offer strong compatibility with Bing, ensuring the necessary cross-pollination for fruit set.
Stella cherry trees are good pollinators for Bing and are self-fertile, meaning a single Stella can produce fruit on its own. Lapins is another excellent choice, also self-fertile, and effectively pollinates self-sterile varieties like Bing. This variety is a hybrid of Stella and Van. The Van cherry tree is a consistently reliable pollinator for Bing, known for its strong compatibility. Similarly, the Black Tartarian cherry is a common and effective pollinator.
Rainier cherries also work well with Bing, offering both pollination and desirable fruit. The Black Republican, a parent of the Bing cherry, is known for its ability to cross-pollinate with many sweet cherry types. It is important to note that Bing, Lambert, and Royal Ann (Napoleon) cherries are cross-unfruitful and cannot pollinate each other.
Key Considerations for Successful Pollination
Matching bloom times is paramount when selecting a pollinator for a Bing cherry tree. Cherry flowers are typically receptive for a short window, often just three to five days after opening. The chosen pollinator variety must have a bloom period that significantly overlaps with Bing to allow for effective pollen transfer. While early and mid-blooming varieties often overlap, and mid and late bloomers can as well, early and late bloomers usually do not coincide sufficiently.
The chill hour requirement is another important factor, referring to the hours a tree needs between 32 and 45 degrees Fahrenheit (0 to 7 degrees Celsius) during dormancy. Bing cherry trees typically require 700 to 900 chill hours for proper bud break and fruit production. Select a pollinator with a similar chill hour requirement to ensure both trees bloom simultaneously and thrive in the local climate. Insufficient chill hours can result in delayed or uneven blossoming, hindering successful pollination.
Tree health also plays a part; choosing varieties with good resistance to common cherry diseases, such as bacterial canker, is beneficial. Finally, the physical proximity of the trees is important. Pollinator trees should be planted within 50 to 100 feet of the Bing cherry tree to ensure bees and other pollinators can efficiently transfer pollen.
Enhancing Pollination Success
Once suitable cherry varieties are planted, several practical measures can help optimize pollination. Honey bees are the primary pollinators for cherry trees, attracted to nectar and pollen. Encouraging a healthy population of these insects is crucial. Planting other pollinator-friendly flowers nearby can attract and sustain bee activity.
Careful pesticide management is also important; avoid application during the cherry bloom period to protect bees. If pesticide use is unavoidable, apply them at dusk or night when bees are less active. Proper tree placement and spacing are beneficial, ensuring good air circulation and allowing pollinators easy access. Standard sweet cherry trees require 35 to 40 feet of spacing, semi-dwarf types 15 to 18 feet, and dwarf varieties 8 to 10 feet.
Environmental conditions during the bloom period can significantly impact pollination success. Cool, rainy, or windy weather can reduce bee activity, leading to decreased pollen transfer. Extremely warm temperatures can also affect pollen viability and the fertilization process. While growers cannot control the weather, creating an optimal environment for trees and pollinators maximizes the chances of a bountiful cherry harvest.