How to Propagate Blueberries

Propagating blueberries is an economical way to expand a crop or start a new garden. There are several methods to propagate blueberries, including growing from seeds, using hardwood or softwood cuttings, or more advanced techniques like tissue culture. Some are more appropriate and preferred for commercial cultivation due to their specific advantages and characteristics.

Growing blueberry from seeds

This is not recommended for commercial production, but it is possible and sometimes applied by amateur growers. Blueberry fruit ripens on average 60-80 days after bloom. The first step is to harvest the ripe fruits and extract the seeds. After that, it is important to clean them thoroughly to remove pulp residues and then dry them. This cleaning process ensures the seeds are ready for their next stage: stratification. Stratification involves exposing seeds to cold temperatures for a few months (they can be placed in the freezer for about 3-5 months), mimicking the natural winter dormancy period required to trigger germination.

After stratification, the seeds are planted in small pots with well-draining, acidic potting soil and covered with a thin soil layer. A light covering of soil ensures they are not buried too deeply, and consistent moisture is maintained throughout the germination period. The pots should be placed in a location with ample light or under grow lights to promote healthy growth. Once the seedlings have developed a few sets of leaves and appear sturdy, they can be transferred to larger pots. Before moving them outdoors, they must gradually acclimate to outdoor conditions to avoid transplant shock. This seed propagation method, while time-intensive, allows for unique genetic combinations, making it particularly appealing to those interested in cultivating novel blueberry varieties.

Growing blueberry from cuttings

For those seeking a faster and more reliable method of propagation, cuttings are the preferred choice. This method can be divided into two types: hardwood and softwood cuttings. Hardwood cuttings are taken from mature, dormant stems during the late fall or winter, while softwood cuttings come from young, pliable stems during the growing season. The cuttings should be taken from the upper part of the mother/donor plant. When you cut any plant, you can use a sharp blade or razor dipped in rubbing alcohol to reduce the injury of the parent plant and to prevent transmitting any diseases.

Hardwood cuttings are the most common way of propagation because they are more manageable. Hardwood cuttings are typically harvested from healthy plants in late winter and stored until the planting date. Keep in mind that cuttings need at least 850-1,000 chilling hours to flower and grow shoots. Stems from the previous year's growth are chosen and cut into 6 to 12-inch (15.2-30.5 cm) long sections. The cuttings are prepared by making a straight cut near the base and a diagonal cut at the top, which helps identify the orientation during planting. Hormonal rooting powder can be applied to the lower ends to encourage root development. When ready, you can open some holes in the soil and insert the cuttings. It is advised to avoid inserting the cuttings directly because the rooting hormone might rob off while you are placing them in the ground. A suitable acidic potting mix should be selected to get the best and fastest rooting. The root cuttings should be placed in a dark place until new shoots form. You can keep the soil moist and transplant them into your garden once they start rooting and growing leaves.

Softwood cuttings, on the other hand, are collected during the active growth phase of the plant in early summer. These cuttings are shorter, typically 4 to 6 inches (10-15 cm) long, and are taken from the tips of healthy shoots. The leaves from the lower portion are removed to reduce water loss, and the cut ends are dipped in rooting hormone. Softwood cuttings require a warm, humid environment, often provided by placing them under misting systems or in propagation trays with a cover. This method tends to root more quickly than hardwood cuttings, with visible results in 4 to 6 weeks.

Both methods require consistent care and attention, particularly to ensure the soil remains moist and the environment supports healthy root development. Once the cuttings have established roots, they can be transplanted to pots or garden beds for further growth.

Advanced Propagation Techniques

Tissue culture offers a sophisticated alternative for propagating blueberry plants. However, this method is mostly used in research and, in some rare cases, in plant nurseries. This laboratory-based method involves growing plants from small tissue samples in sterile conditions. Tissue culture ensures that the propagated plants are genetically identical to the parent and free from pathogens.

Pollination of Blueberry Plants

Blueberries rely heavily on pollination for successful fruit production. Poorly pollinated flower will either produce a small, misshapen berry or fail to develop into a berry at all.

Native bees, such as bumblebees, southeastern blueberry bees, and solitary bees, are particularly effective in pollinating blueberry flowers. Bumblebees and southeastern blueberry bees, which are active in cooler spring temperatures, are often better suited for early-season blueberry pollination compared to honeybees. Honeybees, while capable, are less efficient on blueberry flowers due to their shape and pollen release mechanism. To attract and sustain native pollinators, growers are advised to install and maintain flowering lines around their crops and limit the use of pesticides.

Studies show that a single blueberry flower may need multiple pollinator visits to ensure full pollination. In commercial blueberry farming, growers sometimes supplement natural pollination with managed bee hives, such as bumblebee boxes or honeybee colonies, to cover large areas more effectively. Typically, 2-5 five honeybee hives per acre (or 4-10 per hectare) are recommended, depending on the variety and number of flowers produced by the crop.

References

https://www.canr.msu.edu/uploads/resources/pdfs/propagating_highbush_blueberries_(e1680).pdf

https://beaufort.ces.ncsu.edu/2023/10/propagating-blueberry-bushes/

https://smallfruits.org/files/2019/06/03BlueberryPropagationSuggestions.pdf

https://entomology.ces.ncsu.edu/small-fruit-insect-biology-management/blueberry-pollinators/

https://www.nativenurseries.com/blog/blueberries-are-pollinated-by-native-bees

https://sites.udel.edu/weeklycropupdate/?p=22067

Further reading

14 Interesting Facts about Blueberries

Uses, Nutritional value and Health Benefits of Blueberries

Blueberries vs. Bilberries- Are blueberries and bilberries the same thing?

Blueberry Plant Information-How to Identify Blueberry Plants