Flowering and Pollination – One of the Most Critical Blueberry Growth Stages

By Mark van der Werf, Soft Fruit Consultant, Koppert Biological Systems

Blueberries and bio-stimulants are a strong combination, especially during the spring, when plants are flowering, and pollination is taking place: the right bio-stimulant at the right growth stage can have a major impact on blueberry production and quality.

Spring has arrived in the northern hemisphere, with bees, butterflies and other pollinators becoming more active. Along with many other crops, blueberries rely heavily on pollinators to initiate the production of berries.

But is it only pollinators that are important, or are there other factors to take into consideration?

First stage: bud initiation

There are a few critical periods in the blueberry growth-cycle. The first is bud initiation in the autumn. Before the plant goes into dormancy, the plant is ‘deciding’ which buds will be vegetative, and which buds generative. The more energy the plant has, the more generative buds are initiated. The generative buds are the ones that produce flowers in spring. Poor growth in the late summer/early autumn will limit the number of generative buds, and, consequently, the yield.

Second stage: flowering

Flowering is the second critical period. The flowers on the blueberry bush will pollinate and set fruit in a 2-3-week window, during which the plant experiences a tremendous hormonal shift to support this reproductive phase. In addition to the standard nutrition, the crop requires high concentrations of trace minerals and calcium. If it doesn’t get what it needs to support this hormonal shift, the plant will start to suffer and become stressed, making it an attractive food source for insects and diseases.

Third stage: fruit maturation

The third critical period in the growth cycle of a blueberry plant is fruit maturation, and the growth of new shoots.

Focus on flowering and pollination

Concerns are sometimes raised that the pollinators are not doing a good enough job, resulting in poor pollination. This can be true, of course, but there are other reasons why pollination can be disappointing, including weather conditions (temperature, rainy days, etc.), chemical residues, and the quality of nutrition in the previous (flowering) period. As mentioned above, flowering and pollination demand high amounts of trace elements and calcium, with concentrations in a flower bud at 60-80 times higher than in a leaf.

Although calcium and trace elements can be supplied using standard fertilisers, this is not always sufficient. To support the plant’s extra mineral demand:

• Use the root enhancer Vidi Parva in the spring to improve root mass and quality.
• During the crucial flowering and pollination period, make 1-2 foliar applications of Vidi Terrum (to meet the high demand for trace elements) and Veni Calcium (calcium is very important in the first development stage after pollination); Vidi Terrum contains seaweed extracts, in a plant-based form for rapid assimilation, and Veni Calcium is easily absorbed by the plant due to its unique composition - using a foliar application ensures it is directly available to the plant.

These applications will have a very positive impact on plant performance. Once the number of generative buds has been optimised in the autumn, active nutrition has been ensured, and balance in flowering and pollination has been achieved, everything is ready for a good harvest.

Due to state and federal regulations not all products mentioned in this article are available in the United States. Call your local consultant to find out which ones are and what are best substitutes to reach maximum effectiveness.

Proven results and performance guarantee

The NatuGro system has been tested by 24 strawberry growers in California over 4 years. 85% of the strawberry growers were able to increase their yields by 5 percent or higher, bringing their return on investment to four to five dollars for every dollar spent on NatuGro. Field trials were carried out in the United States from 2015-2018. Trial locations were located in the three major strawberry producing regions in California (Watsonville/Salinas, Santa Maria and Oxnard).

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