Flowering and Leafing of Low-Chill Blueberries in Florida

Abstract

SUMMARY Obtaining high yields of high-quality blueberries early in the season requires cultivars and growing systems that result in plants that have a full canopy of healthy leaves for at least the last 70% of the flowering-to-ripening interval. Florida's two native evergreen blueberry species, V. darrowi and V. myrsinites accomplish this by maintaining healthy leaves from the previous growing season through the time of berry maturity the following year and by producing strong new growth flushes in late winter at or shortly after the time of flowering. Southern highbush cultivars and selections, which are complex hybrids between evergreen V. darrowi and deciduous V. corymbosum range from highly deciduous to mostly evergreen when grown in commercial fields in north Florida. Many selections that maintain most of their leaves through the winter will defoliate before fruit ripening the following spring, leaving the plant without enough foliage to mature a high-quality crop. Profuse vegetative growth in early spring can be promoted by cultivar selection, winter pruning to reduce the number of flower buds, application of hydrogen cyanamide or other defoliants during the dormant season, and control of blueberry gall midge, which kills the apical meristems of new growth flushes.