Selecting a variety can be the key to success for a grower. This choice becomes especially important when we establish a fruit tree orchard since we expect production for many years. As a result, a cherry grower needs to carefully examine his/her options and make an informed decision by taking into account multiple factors. It is highly recommended that each grower discuss with a licensed agronomist from his/her region and fellow growers to learn which varieties are adapted and widely used in the area. Except for the factors listed below, we will focus on the importance of dwarf and semi-dwarf varieties for modern, commercial sweet cherry orchards.
Factors to consider when choosing a sweet cherry variety
- Climate and Weather Conditions – Local Conditions
Keep in mind that sweet cherries require a certain number of chilling hours (hours when the temperature is below 7°C or 45°F) during winter to break dormancy and promote flowering. Different varieties have different chilling requirements, so choosing one that matches the local climate is crucial. For example, 'Minnie Royal' and 'Royal Lee' are suitable for regions with low chilling hours (warmer areas), while 'Lapins' and 'Bing' are better suited for areas with higher chilling hours (colder regions).
Farmers should ensure that the chosen variety and rootstock are adapted to the specific characteristics or constraints of the soil in their orchards. Except for the type of soil, the pH is another important characteristic to take into account.
Of course, at the same time, the farmer should take into account the cold hardiness of the variety, especially in regions with lower temperatures and higher risk of frosts. Early blooming varieties may be more susceptible to frost damage. Farmers in regions with late spring frosts should choose varieties with later bloom times to minimize the risk of flower damage. Additionally, some varieties are more tolerant of heat or cold than others. For instance, 'Stella' and 'Sweetheart' are known for their cold hardiness, while 'Royal Rainier' is more heat-tolerant.
- Pollination requirements
Some sweet cherry varieties are self-fertile (e.g., 'Stella,' 'Lapins'), meaning they do not require another variety for pollination. However, most varieties require cross-pollination from compatible varieties to set fruit and succeed in higher yields. When choosing your main variety, be sure to select at least 2 (or even 3) compatible pollinizer varieties that cover the whole flowering period (of your main variety) to ensure a successful fruit set.
- Market Preferences and Productivity
Market demand often dictates the preferred fruit characteristics. Larger, firm cherries with attractive color and good flavor typically have higher market value. Varieties like 'Bing' and 'Rainier' are popular in the fresh market due to their desirable fruit qualities. "Strawberry" sweet cherry varieties (fruits with pinkish color) become more and more popular in recent years. At the same time, farmers know they can get higher prices in periods with less fruit availability (early or late in the season). For this reason, early or late-season varieties might be selected. In the past 10-20 years, with the rise of dwarf and semi-dwarf varieties and the high-density planting systems, the tree's longevity may also be an extra factor that the farmer needs to consider (since replanting might be needed in a shorter period).
- Resistance to pests/diseases and planting system
The farmer should be aware of the common pests and diseases in his/her region, which can put the trees and production at risk. Knowing that will give him/her the opportunity to select resistant or tolerant varieties and rootstocks. Additionally, as mentioned above, if a grower wants to have a high-density orchard to obtain its advantages, he/she needs to select appropriate varieties and rootstocks for this system (Dwarfing and semidwarf varieties vs. traditional varieties, presented below).
Dwarf and Semi-Dwarf Sweet Cherry Varieties and Rootstocks
Sweet cherry cultivation has evolved significantly over the past few decades, with a growing preference among farmers for dwarf and semi-dwarf varieties. These modern orchard systems offer several advantages over traditional cherry trees, making them an increasingly popular choice worldwide. Below, we will focus on the reasons behind this trend, the benefits of these varieties, their training methods, planting distances, and the most popular varieties and rootstocks used globally.
Why Modern Farmers Prefer Dwarf and Semi-Dwarf Sweet Cherry Varieties?
The advantages of dwarf cherry varieties
Modern cherry growers usually prefer dwarf and semi-dwarf sweet cherry varieties due to several key advantages:
- Greater Precocity: These varieties tend to enter the reproduction phase (fruit-bearing phase) earlier than traditional cherry trees, allowing farmers to achieve a faster return on investment.
- Better use of available space: The smaller size of dwarf and semi-dwarf trees allows for high-density planting, leading to increased yields per hectare or acre. This is crucial in maximizing productivity and profitability.
- Easier Management: The reduced size of these trees makes maintenance tasks such as pruning, harvesting, and pest management easier and more efficient. Additionally, dwarf and semidwarf varieties are usually trained into the Central Leader System or as V/Y Hedges, allowing better coverage by the plant protection products or foliar fertilizers. The smaller size of these trees facilitates harvesting and leads to better worker safety and productivity. Accessing and collecting the fruits without the need for ladders or specialized equipment streamlines operations and reduces labor costs. As an indication, a worker can harvest approximately 100-150 kg of cherries within 8 hours. Of course, the collection of the fruits should be performed with care to avoid bruising the fruits (which could reduce their commercial value and storability). At the same time, as we further analyze in the article devoted to Cherry Harvesting, workers should be very careful not to break or damage the spur (fruiting twig). The spur is required for future years' production.
- Improved Orchard Protection: Smaller trees are easier to protect from environmental hazards such as rain, hail, and birds. Growers can install protective netting or covers over the orchard (since the trees are shorter).
- Enhanced Fruit Quality: High-density planting systems can lead to improved fruit quality through better canopy management and optimized sunlight exposure.
Despite these advantages, high-density systems come with risks, such as potential small, poor-quality fruit if not properly managed. Thus, carefully considering site conditions and management skills is essential before adopting this system.
Higher density orchards
- High-Density Orchards: One of the most commonly used systems in modern commercial cherry orchards. Dwarf trees are typically used and planted at a spacing 3 x 4 m (10 x 16 ft) or 3.5 – 4.5 m (11.5 x 14.8 ft), accommodating about 840 trees per hectare (340 trees/acre). This allows for optimal sunlight exposure and canopy management. To fit this system and planting distances, dwarf varieties are used.
- Standard-Density Orchards: They have fewer than 740 trees per hectare (300 trees/acre), and semi-dwarf varieties are planted. Common planting distances used are 5 x 5 m and 5 x 6 m (16.4x16.4 ft and 16.4x20 ft)
- Ultra-High-Density Orchards: Feature even closer spacings (1.8 x 3.5 m or 6 x 11 ft) with more than 1630 trees per hectare (660 trees per acre). This system is still not widely used due to its challenges.
- Traditional Orchards: Cherry orchards with large cherry trees are still common since they were planted 20-30 years ago and remain productive (so they have not been replaced by new trees—dwarf varieties). In such orchards, the planting distances are bigger, usually 8 x 8 m, 9 x 9 meters, 7 x 10 m and 10 x 10 m or more (26x26 ft or 30x30 ft, 23x33 ft, and 33x33ft).
In these higher-density systems where dwarf and semi-dwarf varieties are cultivated, common training systems are the central Leader, the Spindle Canopies, the Spanish Bush, Tatura Hedge, V/Y Hedges, and Multiple Leader Bush (KGB).
Differences from Traditional Sweet Cherry Varieties
Traditional sweet cherry trees are typically larger, require more space, and take longer to bear fruit than dwarf and semi-dwarf varieties. Due to their size, they are generally more challenging to manage, necessitating more labor-intensive pruning and harvesting processes. Additionally, traditional varieties may not be as adaptable to modern high-density orchard systems, limiting their potential for maximizing yield per hectare or acre.
Dwarf and semi-dwarf sweet cherry varieties usually start producing fruit within 2-3 years and reach maximum yields after 4- 5 years after planting. These varieties can give good yields for 15-18 years or, in some cases, up to 25 years. The average production of a 5-year-old semi-dwarf tree could be around 20 kg per tree (per year) (44 lbs/tree/year). Commercial growers start planting the new trees 1-2 years before replacing their older crop in the lines between the well-grown trees. This way, they will receive a good production quickly, without losing years. These fruits are marketed for raw/fresh consumption. Sweet cherries for raw consumption should be larger than 24-26 cm (9.4-10.2 in). The bigger the cherries, the higher their marketable price.
On the other hand, traditional varieties are much bigger and start producing fruits 6-7 years after planting and remain productive for 40 to 50 years but with declining yields after 30 to 40 years. Depending on the variety, the cultivation practices, and the region, these large trees can give even up to 500 kg per tree (per year) (or 1102 lbs per tree/year). Nowadays, large parts of the fruits of these trees are used for industrial use and processing (fruits with sizes around 18-22 cm (7-8.6 in) or smaller), but they can also be consumed fresh.
Popular Sweet Cherry Varieties and Rootstocks
Dwarf and Semi-Dwarf Varieties
- 'Lapins': Known for its self-fertility and excellent fruit quality.
- 'Stella': Another self-fertile variety, popular for its large, sweet fruit.
- 'Gisela' Rootstocks (Gisela 5, 6, and 12): These are among the most widely used dwarfing rootstocks known for their early fruiting and adaptability to different cherry varieties.
Popular Rootstocks
- Gisela Series (Gisela 5, 6, 12): Developed in Germany, these rootstocks are known for their size-controlling properties and early fruiting. However, they require intensive management to maintain fruit size and yield.
- Krymsk Series (Krymsk 5 and 6): These rootstocks offer semi-dwarfing characteristics and are adaptable to a wide range of soils and climates. They are especially popular in regions with cold winters.
- MaxMa 14: A semi-dwarfing rootstock suitable for high-density plantings, known for its resilience to calcareous soils and iron deficiency.
- Mahaleb and Mazzard: Although less commonly used today, these traditional rootstocks are valued for their adaptability to various soil types and conditions.
Traditional Rootstocks
- Mahaleb (Prunus mahaleb): Known for its drought tolerance and used for traditional cherry varieties.
- Mazzard (Prunus avium): Offers good compatibility with a wide range of sweet cherry varieties and is cold-hardy.
Global Cultivation and Popular Varieties
Sweet cherry cultivation varies by country or even region, with certain varieties and rootstocks preferred for their adaptability to local climates and conditions.
- Europe: Popular varieties include 'Ferrovia,' 'Regina,' and 'Grace Star.' Rootstocks like Gisela 5 and MaxMa 14 are commonly used.
- North America: Varieties such as 'Bing,' 'Rainier,' and 'Lapins' are favored, often grafted onto Gisela or Krymsk rootstocks.
- Australia and New Zealand: Varieties like 'Stella' and 'Sweetheart' are common, with Tatura hedge systems and Krymsk rootstocks widely adopted.
There are many more sweet cherry varieties available on the market to choose from. Be careful, do your own research, and consult a licensed local agronomist before choosing a variety and planting your cherry trees. As research and breeding programs continue to advance, the options for cherry growers are likely to expand, offering even more opportunities for innovation in this dynamic industry.
References
https://www.cabidigitallibrary.org/doi/book/10.1079/9781786398284.0000
https://ipmdata.ipmcenters.org/documents/cropprofiles/WAcherries-sweet.pdf
https://njaes.rutgers.edu/pubs/commercial-tree-fruit-guide/08-Cherries.pdf
https://www.govinfo.gov/content/pkg/GOVPUB-A-PURL-gpo25996/pdf/GOVPUB-A-PURL-gpo25996.pdf
https://www.cherrygrowers.org.au/assets/australian_cherry_production_guide.pdf
https://appliedecon.oregonstate.edu/sites/agscid7/files/oaeb/pdf/aeb0070.pdf
https://journals.ashs.org/hortsci/view/journals/hortsci/50/1/article-p59.xml
Further reading
Cherries: Info, Facts, Nutritional Value & Health Benefits
Plant Information of cherries
10 Interesting Things About Cherries You Probably Didn’t Know
Growing Cherry Trees for Profit
Soil requirements, preparation, and planting of cherry trees
Cherry Tree Water Requirements
Cherry Tree Propagation and Pollination
Cherry Tree Training, Pruning, and Fruit Thinning
Cherry Tree Fertilization
Cherry Tree Pests and Diseases
Cherries Harvesting and Yield per Hectare – Do you pick cherries with the stem on or off?
