Highbush blueberries grown in Michigan often require seven to ten years from planting until peak fruit production. Preventing young plants from producing fruit for three years after planting increases vegetative growth and reduces this time interval. Manual removal of floral meristems is recommended, but labor intensive. Less costly methods to prevent fruiting are needed. Studies were conducted across several years to determine the efficacy of plant hormones in preventing fruiting and to determine the growth pattern of young highbush blueberry cultivars currently being planted. The majority of shoot growth occurred from May to July in the first and second growth flush. Floral buds were found on the first, second, and third growth flushes, with the majority on the second flush in 2012 and on the first flush in 2013. The pattern of floral bud distribution between growth flushes indicates a lengthy floral initiation time interval. Foliar gibberellins (GA) applications reduced the number of floral buds up to 49%, with the greatest reduction occurring when GA was applied multiple times from July to October. Auxin applications showed inconsistent results. Cytokinin (BA) applications in the spring reduced fruit set, but also reduced vegetative growth. Manual removal of floral structures resulted in more vegetative shoots per plant and canopy growth compared to non-treated plants.
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