Effect of Summer Hedging on Return Bloom, Yield, Tree Growth, and Juice Quality of Apples Grown for Cider.

Foster, J. Kingsley-Richards, S.L., and Bradshaw, T. 2022. Effect of Summer Hedging on Return Bloom, Yield, Tree Growth, and Juice Quality of Apples Grown for Cider. Acta Hortic. 1346, 439-446. Abstract: As growers have started planting specifically for the production of fermented cider, new information is needed to understand how to maintain adequate annual crop yields and improve return bloom. Cider cultivars of European origin have been found to respond poorly to traditional crop load management methods using plant growth regulators and traditional return bloom sprays. In this study, tall spindle-trained cider apple ‘Somerset Redstreak’ and ‘Harry Masters Jersey’ and traditional dessert apple cultivars ‘McIntosh’ and ‘Empire’ were mechanically hedged in summer 2019 and 2020 to evaluate response on return bloom, yield, tree growth, and juice quality. Treatments consisted of 1) normal winter dormant pruning; 2) mechanical winter dormant pruning with a hedger; 3) mechanical pruning at pink (pre-bloom) bud stage with hedger, and 4) mechanical pruning at 12-14 leaf stage in mid-June. ‘McIntosh’, ‘Empire’, and ‘Somerset Redstreak’ each flowered and cropped in 2020, but ‘Harry Master Jersey’ had essentially no crop and was not affected by hedging. There was a noteworthy difference in canopy size for all cultivars during the first season, with most hedging treatments being reduced nearly by half. Juice quality was unaffected by hedging treatment for soluble solid content, pH, titratable acidity, and total phenolics. Continued evaluation is needed to understand the long-terms effects hedging has on return bloom.